Green Cottage: eco-renovation of a 100-year-old Victorian end-terrace

This is a guest post from Andy Hunt (solar_bud on The Oil Drum). It's an inspiring account of what can be done today with a modest property to live efficiently and maintain a degree of energy security.

Vital Statistics

Our house was built around 1900. It is an end-terrace house with 2 bedrooms, located in an inner-city area in Bury, Lancashire, UK. Our household comprises me and my partner, with no children, and we live in the property all year round. No planning restrictions are in effect in our area.

Wood burning stove with back boiler.

Annual Energy Use

We use around 3200 units of electricity annually from the grid, although this is expected to fall once we install the second stage of our solar PV system. This includes all cooking, as we don’t have a gas supply, and is about average for our part of the country.

Our heating system is 100% wood and solar fuelled, so we don’t tend to count heating in our energy consumption. We go through quite a few logs over the course of a winter though!

We use a ‘green’ electricity tariff, initally Npower “Juice” but now Good Energy as it's 100% renewable unlike Juice.

About Us and Why We Did It

I work as Sustainability Manager for a local Council, and have a long-standing interest in energy issues, climate change and fossil fuel depletion. I have always wanted to live in an eco-house, and my home renovation project of our very ordinary Victorian terraced house has made that dream a reality.

My partner comes from a family whose motto is “mend and make do”, and she has grown up with solid fuel heating all her life. She is very practically minded, the daughter of an electrician, so her ideas and practical suggestions have been a very valuable part of our ‘green’ experiment.


The existing gas central heating system was converted to run on wood fuel and solar power.

I hired a plumber who disconnected the existing radiator system from the (cheap and low-quality) gas combination boiler which was running it when I bought the house, and connected it up to a new wood burning stove which was installed in the fireplace in the living room. The stove has a back boiler which runs two pipe loops – one connects the stove to a dual-coil hot water storage cylinder in the bedroom directly above, and the other connects the stove to the radiators in the house.

The hot water storage cylinder is heated by convection from the back boiler, and on the return pipe from the cylinder to the stove is a pipe thermostat. When the temperature of the return pipe (and hence the water in the cylinder) reaches 60°C, the thermostat starts a circulation pump in the radiator circuit, which pumps hot water around the house. This ensures that the hot water cylinder is heated as a priority, and is kept hot at all times.

When choosing a wood stove, it is essential to choose the right type for the application and situation. An ordinary room heater stove will provide warmth and cooking facilities in an emergency such as a power cut. A larger stove with a back boiler like ours can also run a central heating and hot water system, but is more expensive to install.

If you live in a smoke control area, you must legally install a stove which is exempt from the Clean Air Act by DEFRA for burning wood in a smoke control area. Most stove manufacturers make such models, but at the time of writing the only wood stove with a back boiler which is CAA-exempt is the Dunsleyheat Yorkshire stove.

In the summer, the cylinder is heated by a solar hot water system, which is plumbed into the lower coil in the hot water storage cylinder – the wood stove is plumbed into the top coil. Our solar hot water system is by Zen Eaga Solar – it is a flat plate system, and works well. Most solar hot water system installers will provide a dual-coil cylinder as part of the installation. The cost of the cylinder is actually a substantial part of the cost of the whole system.

Power Generation

The house uses solar photovoltaic panels and a battery back-up system for power security and low carbon emissions.

In the house there are two ring-mains - one which serves the heavy duty appliances in the kitchen such as the hob, cooker and washing machine, and a second one which serves the rest of the house.

When considering solar PV for electricity generation, I didn't like the idea that I would still lose power during a power cut if the system was grid-connected. So I went for a hybrid system, which doesn't feed excess power into the grid but stores it in batteries, will work during a power cut for several days, and can also take mains electricity when it is available.

We currently have 330Wp of solar PV (to be expanded to around 700-900Wp soon), connected to a 720Ah battery bank and an inverter-battery charger, which serves my second (low power) ring main. The inverter/charger is a Powermaster 1.5kW pure sine wave inverter which can take a 240V mains input, or can run off the batteries and solar PV in the absence of mains electricity. It was originally designed for use aboard boats, and so we just use the grid as our ‘shore power’ equivalent. Interesting to think of our home as a ship afloat at sea when we are running off-grid! Our PV panels are currently two Schüco 165Wp polycrystalline panels – the next stage will see an additional 165Wp Schuco panel plus a 200W Kyocera polycrystalline panel, bringing our installed capacity to 695Wp. The 30A solar controller on the inverter/charger can take up to 1kWp of solar, so even then there will still be room for another 200-300Wp of PV, as long as we can find the roof space for it!

In the summer the system will run for around a week at a time before the batteries need to be recharged from the mains. Further PV addition should improve this so that it runs pretty much constantly over the summer months. In the winter when the PV isn't generating as much, the batteries can be charged from the mains and in UPS mode the inverter will switch over to the batteries during a power cut, which will last us for 3 days or so, giving us desk lamps, TV (using a laptop and TV card), central heating pump, solar pump and general electrical gadgetry which makes life much more bearable during a power cut.

The only things we can't use during a power cut are the heavy-duty kitchen appliances. The fridge can be plugged into the off-grid ring main during a power cut with an extension reel.

Batteries and inverter.

Water and Sewage

We have only made fairly basic water efficiency improvements at Green Cottage - the installation of two water butt in the garden holding around 450 litres, a dual-flush toilet and spray nozzles on the bathroom taps all help to reduce water consumption.

We do have a dishwasher and a washing machine but they are both 'A' rated for energy and water efficiency. Studies have shown that dishwashers make more efficient use of water and electricity than washing up by hand, and we have a manual ‘wonder washer’ for clothes which we can use during power cuts. Our dishwasher is a very new model, and the instructions give details on how to connect it up to make use of solar-heated hot water. However, we tend to use our solar hot water for baths and showers only, so the dishwasher is actually connected to the cold water supply in our case. Not ideal, but with British summers the way they are, we need all the solar power we can get just for washing ourselves!


We have had the standard 250mm of loft insulation installed under a Scottish Power discount insulation scheme a few years ago - most utilities offer these schemes under the Government's Energy Efficiency Commitment. You can find out which are the cheapest schemes in your area by telephoning your local Energy Efficiency Advice Centre on 0800 512 012.

Unfortunately our house does not have a wall cavity and so we can't install cavity wall insulation. We have no intention of getting external insulation done - far too expensive! The nice thick Accrington brick walls of our home give a good thermal mass though.

Summer Cooling

The high thermal mass of our old house helps to keep it cool in the summer.
We are lucky in that our living room is on the North-facing side of the house, but houses the wood stove which heats the house in the winter.

This arrangement means that in the winter, the living room is the warmest room in the house, and in the summer it is deliciously cool, even in the hottest weather. The high thermal mass of the house means that the North side stays very cool, like a larder, even whilst the back of the house is baking in the midday sun.


All the lights in the house are Compact Fluorescent Lamps, otherwise known as energy-saving bulbs.

We tend only to use low-power desk lamps rather than the 'big light' in each room. As the desk lamps run from the solar PV/battery system, this means that we get free electricity to run the house's lighting, and also that we have lighting even during a power cut.


All appliances are energy efficient appliances, under the European rating system.

The kitchen appliances are 'A' rated, with the exception of the fridge, which although old is still working. Rather than scrap it and buy a new one, we invested in a 'Savaplug', which regulates the motors on old fridges and reduces their energy consumption.

We watch television on a laptop computer with a LCD monitor, and a TV card, which uses very little electricity. The same computer doubles up as our stereo CD player and DVD player, which means we have very little entertainment technology clutter.

Even with 100% electric cooking, our electricity bill is very low, typically around £5-6 weekly.

One measure we have recently taken to cut our electricity consumption is a flat-bottomed kettle to go on our wood stove – electric kettles use huge amounts of electricity, and our £3 aluminium stove-top kettle from Ikea will hopefully make a significant difference to our electricity bill!

The Garden

Although just a small terraced house back garden, ours is crammed with food plants, biodiversity and storage areas.

Our back garden is South-facing, and has been planted up according to Permaculture design principles.

A huge variety of perennial fruits and berry plants are crammed into a small area, with an additional raised bed for growing annual vegetables.

Perennials include: strawberries, blackcurrants, redcurrants, whitecurrants, blueberries, a grape vine, apple tree, pear tree, raspberries, cranberries, blackberries and hazelnuts.

We have tried a variety of different things in the raised beds – the most successful to date have been carrots, pak choi, tomatoes (although we have had problems ripening them as they grow against an East-facing wall), French beans, onions, potatoes and a pumpkin which we have just harvested. We also had a butternut squash plant in the miniature greenhouse which did very well, although the pot it was in turned out to be too small for it in the end.

A storage space for logs, a bunker for kindling, a small lean-to greenhouse and a table and benches for enjoying the sun are all crammed into this typical small terraced house back yard. Space has even been found for a network of four small wildlife ponds and wildlife areas amongst the food growing, and the garden has a significant population of frogs, which is good because slugs and snails are a big problem. We use copper ‘slug rings’ to try to keep small plants safe, but it’s a constant battle, and I may well try other approaches in the future such as beer traps.


It has taken a good few years to get from standard gas-heated end-terrace to low-carbon eco-cottage, a lot of hard work, improvisation and a reasonable chunk of hard-earned cash, but we love the end result. The old gas combi used to really struggle to heat the house, but the wood stove system warms the brickwork through, and we are really cosy. It's also great not having to use any kind of heating in the summer, as the solar hot water system provides us with a cylinder full of free hot water, and even the solar pump runs on free electricity.

I'd like to thank Powerswitch for the inspiration, help and encouragement provided on their forums.

There's nothing quite like relaxing in a hot bath knowing it has been heated free of charge by the sun, and free veggies from our back garden taste so much better than from the supermarket. A couple more PV panels and we will be finished. And then, we might start looking for a small patch of woodland for our next project...

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First published in Permaculture Magazine - solutions for sustainable living.

Wood burning stoves are great provided few other people have them. Unfortunately there's not a great deal of forest in the vicinity of Bury, so popularising this form of heating could lead to serious supply problems. No mention is made in the article of home insulation, a far more cost effective means of reducing fossil fuel consumption than expensive PV panels (especially near Manchester!)and without the abovementioned supply constraints of buringn wood. Would this lack of insulation be partly due to the age of the house? I guess it does not have a cavity wall. Unfortunately, this highlights the problem the UK has with greening its very old housing stock. The only way to insulate the walls of most pre-1920s housing stock is by building further internal walls, greatly reducing the living space, not to mention covering up all those "original features" that make the houses desirable in the first place. I fear that the best solution might not be to refurbish our old houses but pull them down, something that appals the aesthete in me.

Sorry to be so negative in view of all your hard work.

I've never heard of anyone building an extra internal wall for insulation, it seems a bit extream. If insulation is needed its added to the outside of the building but as the original poster said its expensive (for what it is).

In the UK out of a total generating capacity of around 75GW around 25GW is due to go out of commission by around 2015.
It takes years to build nuclear or coal, and the relatively intermittent wind power is supposed to be built off-shore, won't be ready by 2015 or even 2020, costs at least twice as much as nuclear power and still needs a lot of back up.
The governments plans, in so far as it has any, are to import gas which is not likely to be available and will cost a huge amount - and besides which we still have to build the stations.
Power cuts are inevitable and gas is also likely to be in short supply.
Under the circumstances extra internal walls sound like rather a good idea, even though many British homes are quite small and it would take another chunk out of the room inside, that will be the least of our worries.

As an experienced bricky I've never seen it done.
Its actualy more difficult than just reducing the internal room size and has more to do with damp building up within the cavity.
I have seen an extra skin of brickwork go up on the outside of existing buildings though. I would think that this is even more expensive than gluing the insulation to the outside wall and skimming it with render which is far more common.

I just read yesterday about the UKs upcomming energy problem. Arnt there several other European countries about to hit the same wall with decommisoning nuclear power plants and nothing to replace them?

I don;'t really know all the ins and outs - no-one would have considered doing it until recently.
Here is the stuff I was looking at:
Celotex Insulation | High Performance Thermal Insulation Boards
Lafarge Plasterboard - Thermalcheck boards

Some of the versions have some stuff to keep the damp back.
My place has insulated cavity walls - any idea if that helps with the damp?

I did not really go into the full picture of how bad things are likely to be - we are also perhaps unlikely to get full gas supplies - at the moment we are running a £50 billion current account deficit and a 3.5% budget deficit - the last recession we went into it running a 2% surplus and still ended up way in deficit.
That was without peak oil.
Things here are going to get really hairy in my opinion, with no heating or light for long periods.

I don't know as much about the situation of other European countries, obviously.
However, in a brief run-down Holland and Germany both have a housing stock which uses around three times less energy than ours, as they are properly insulated.
Germany is trying to close it's nuclear plant, but will probably have to change its mind.
I don't know how the schedule there is for plant retiring.
France is running about a 2% budget deficit.
They have 59 nuclear reactors which produce 80% of their electricity, are vigorously installing wind, are planning to install 5 million solar thermal water heaters, and are installing 50,000 air heat pumps a year.
They also have substantial wood resources, and many in the country can use that for heating.
For transport they are rapidly installing urban light rail.
Scandinavia is also well placed.
Southern Europe has poor finances, and will likely in a recession not be able to stay in the Euro.
Spain and Greece are heavily dependent on the tourist industry, and with cheap flights on the way out, to go with the housing slump and their awful finances, are arguably in a worse position than Britain.
In summary, Britain is ill-placed to weather the storm, much worse than it's nearest neighbours.


Can I gently encourage you to use paragraphs? They really do help with organizing what you read. Without them, one can get lost as to when a point is done.


Thanks for the reminder - I was dredging so deep to try to remember the little I know about the obsolescence rates of German col plants and so on that I forgot! ;-)

OK I checked out those two sites and think this might be a good idea. I couldnt find any prices but its possible to internaly insulate 1 room at a time this way and therfore not break your budget. I would definatly start with the living room.

A standard British cavity, for buildings 20 years old will have been insulated. Old building possibly not but as long as the cavity is sealed well you wont have problems. If you have problems you would already see the damp on your internal walls. I only ever worked on one job in South London where the walls were constructed for thermal efficiency. They were 200mm thick compared to the standard 60mm.

I'm living in Holland myself but dont have a good grasp of the language yet so its difficult to follow whats happening. I know that recently they began a big project up in Amsterdam to double glaze thousands of council homes.

My personal situation is not so good. I live on a houseboat constructed entirely of wood except the metal hull. An average wall is 30mm wood/60mm insulation/20mm wood. The roofs are flat and of the same thickness and all the windows are single panes. My propane gas bill for heating was astronomical this last winter even with an efficient wood burner in the living room. My only advantage is I can collect a lot of free wood from along the canal. I guess this year I'm going to need a lot more :/

Unless your boat is very large, I doubt it will apply to your situation, but for those boats which have generator I am wondering whether a heat pump is a possible solution?
Certainly on land a body of water is the ideal heat source for a system - can anyone make some sense of this idea?

I've never heard of anyone building an extra internal wall for insulation, it seems a bit extream.

That would depend on how you went about it. Some variation on this idea (Not new, apparently, but this is the only version I've actually seen plans and final products for. I've seen references to "envelope" design as early as the '70's.) should be effective. I am planning to incorporate some version of this in a home if I build one.


Pulling a lot of them down (14 million?) and starting again has been suggested in the 40% House report

I can't see this being particularly popular.

I would urge the use of internal insulation - you may think you're losing space, but you'll gain a lot of comfort. My spare bedroom has solid brick walls and is very small (so small that I've had to have a specially short mattress made). I've put 50mm insulation in the walls, but this enables me to actually put a bed against them and feel cosy without having any heating on. Better a small cosy room than a slightly larger uncomfortable one.

As for 'internal walls' for insulation, I have done this in my neighbour's cellar. I've put 50mm rockwool against the cellar wall and then used metal office stud partitioning framing inside to hold the vapour barrier and plasterboard. I didn't want to use wood because of damp.

As for 'original features', replacement ornamental plaster mouldings are available in B&Q and I even got my mother to make plaster of paris copies of some of the 'modillions' (there's a word or you) that decorate our hall ceiling.


Re my previous post, my apologies! You do mention insulation (albeit briefly), and the lack of a cavity wall. I'm not convinced of the benefits of high thermal mass walls, typical of old houses. High thermal mass means they soak up a lot of energy in cold weather!

Hi bill h,

Thanks for your interest. Firstly, there's no way I am getting external thermal cladding, it costs far more than I can possibly afford, and I think I am fairly typical of terraced home owners in not having thousands of pounds to spend on thermal cladding. You may well be right about thermal mass, but fortunately or unfortunately that is what I am stuck with. You have to remember that this is an eco-renovation, not a new build. I could be guilty of 'looking on the bright side', possibly. As for demolition, that is certainly an option that many councils have taken in many cases across the country - but I doubt it would be resource efficient to extend it to every single Victorian terrace in the country, to be honest.

I have not written much about insulation because what I have written contains all the salient facts for my particular house. This isn't a 'best practice' paper, it is about what I myself have done! Although obviously it could be replicable. The insulation scheme I took advantage of is subsidised by the energy companies, a route which most people in my situation would go down, and which I have mentioned in the article. I could certainly have super-insulated the loft with 500mm+, but I would not have been able to take advantage of the subsidised scheme, and I think many people in my situation would probably do the same. As such it's probably a good case study of what the UK government thinks is satisfactory in terms of insulation, rather than 'best practice' - if you see what I mean.

Regarding your other points, they are fair points. When I posted a link to this article on another website, I included the following 'disclaimer':-

"There are a few caveats here, not everyone could use wood fuel heating as there isn't enough of it. But for terraced houses it might be OK, as they have chimneys and are suited to solid fuel heating. Bigger homes would probably benefit from heat pumps or similar, which just need a bit of electricity to drive them.

It's not a perfect solution either - my PV system is undersized and I will need to add more panels to give me enough power to run the things I need to run, which will mean more cost. And electric cooking is not the most carbon-efficient, although you can get induction hobs which are more efficient than normal ones and we're on a 100% 'green' tarriff for the grid electricity we do use.

If the sun doesn't shine, that means tepid showers rather than a nice hot bath when you feel like it - not something everyone would want."

I would add to this that my supply of logs comes from a local tree surgeon for whom it is waste wood - I have done a little research into this and there is a lot of slack yet to be taken up in this area, including huge quantities of waste wood from council operations - something which is true of pretty much every borough. An alternative to wood heating could possibly have been an air source heat pump, something which National Energy Action (UK fuel poverty organisation) have recently successfully tested in terraced homes, but I would then have needed either underfloor heating or a new set of convecting radiators. In any case, when I was doing the renovation there were no domestic size air source heat pumps on the market so it wasn't an option. So logs we have.

We do go through a LOT of logs though - if I was eco-renovating a terrace for sale, I think I would do it differently - I would keep the gas central heating and just install a room heater wood stove. There is anecdotal evidence of people reducing their gas heating bill by up to 2/3 just through the use of a room heater stove (which of course works in a power cut).

I could have kept my hob connected to my original gas supply (which would have been more carbon efficient than moving to electricity, and would still have worked in a power cut unlike my eventual set-up), but I didn't really want a gas supply coming into the house for just a hob and nothing else, especially in view of the fact that I use solid fuel heating in winter. During power cuts we have cooked on the wood stove though.

It would probably be a more efficient use of the energy my small amount of PV generates to have a grid-connected inverter, although that wouldn't have given me the security from power cuts that my current set-up with a few batteries has. Some people I have spoken to are unconvinced of my need for batteries - we shall see. They will run such things as the solar pump, central heating pump, all my desk lamps, internet, TV etc etc during a power cut though, so life could be a bit more bearable if we start getting them regularly.

I'm sure there are plenty more things wrong which could be better, but I can't think of any more just at the minute!

Oh, except our bath, which is a big and comfortable corner bath, and as such takes a lot of water to fill. We always say it's a water-saving bath though - even though it takes more water, you can get 2 people in it, so per person it's probably quite efficient! :-)

Hi Chris,
Thanks for your post, especially the electricity back-up provisions.
I renovated 3 houses in Winnipeg Canada in the 1980's, using an available government subsidy. All were 3 story brick, build about 1900-1910. The first thing we did was put 60cm insulation in ceiling, 10cm against walls of basement by adding 4''studs and replacing windows.It seems you have single glazed aluminum. These are usually very poor, leak air and conduct heat. We replaced old single glazed windows with double glazed insulated core wood casement windows, which shut air-tight but can open fully in summer. We also replaced doors with insulated core doors, with draft stoppers. A lot of heat escapes from air-exchange, in most houses its like having one window fully open. If you feel cold drafts around windows or doors when wood stove is on, you may be having one full air change every 15 mins.
An air-tight house ( one air exchange every 2-3 hrs) will not allow a wood stove to draw so you have to have an cold air inlet to the back of the stove to replace hot air lost.
On two of the houses I did add internal wall insulation( 10cm), but this was the most expensive, not economic if you do not control drafts. We found we did not have to turn on heat until outside temperature was about -5C, so not sure how much savings you would get burning wood, if house is draft free. Its also a lot more pleasant. Window replacements are expensive but can do over several years, one or two at a time.

Back in the mid 1990's I rennovated a victorian terrace. If you strip the old plaster back to the brickwork and then fix insulated plasterboard the space loss is minimal. I worked in 700 square feet of plasterboard with 40mm polyurethene insulation. As for thermal mass the internal walls and chimney blocks provided sufficient heat capacity

And history shows that big thick walls are just what people choose if they build their own homes in cold areas unhampered by planning regulations. Often to save on wall material they'd build the house half into the ground, so that the ground would act as a "large thermal mass".

For example, below is an Iron Age hut in Britain, similar ones were built in Germany, Scandanavia and Russia right up until the Middle Ages. You can see it has quite a thick wall, in

They didn't live on an earthern floor, they had a wooden floor a couple of feet above it, between the wood and the earth they had straw, which as it decayed over winter helped heat the place.

If you ever camp out overnight, what you find is that the earth itself doesn't change much in temperature. It warms up a bit during the day, and then slowly releases this heat overnight. It takes some months of winter and snow before the earth will freeze.

However, if this earth is associated with a house, it won't freeze. In Germany with their "passivhaus" design, what they've found is that if you insulate the thing enough, just the heat from the bodies of the people in it is enough to keep it at an even temperature. Adults radiate about 100W of heat. That's not a lot, but it's enough if the place is very well-insulated. Designers of shopping malls and cinemas have to account for the people in buildings and rooms in terms of keeping an even temperature in the places. A typical cinema seating 400 people has the equivalent of 40,000W of heating, that's like 40 of these,

It's possible to use this in our favour as well as have to accomodate for it. If you can insulate your home sufficiently, human body heat will go a long way to reducing how much artificial heating you need.

You can believe large thermal masses help in this, or not, as you wish. But the fact is that people built homes in cold climates with large thermal masses for thousands of years and managed to survive. You can learn from history, or deny it as you wish.

Hello, as with everything else, looking at just one element doesn't tell you much. Think of a log home with clay between the logs, not well fitted. In summer, this is probably not a bad configuration, but winters would likely be cold any distance from the fire due to drafts, etc.

Now, take that same home and have finished, tongue-in-groove, 4x4 beams then you've got the beginnings of a different story. Use some kind of glue or other sealant, compress the logs together like they do straw bales, seal the corners well and have a well-designed, sealed roof, passive solar front to the structure and - viola! - you just might have quite a little home.


Andy - one regulation I've come across in the UK on wood burners is the requirement to have a structural hearth extending for 2 ft beyond the front of the stove.

This to my mind is totally and utterly idiotic like most else that is going on in the UK right now. The hearth below a stove does get hot - but nowhere near combustion point. In front of the stove it only gets warm. The danger of course is that a burning log falls out, so it makes sense to have a decent stone hearth (floating) in front of the door to protect against this real hazard. But I don't see it is necessary to have that hearth extend all the way down to the Earth's mantle.

Are you able to advise on the regulations and what you think of them.

Hi Euan, I can't honestly say I've heard of that bit of regulation, I'll check with some colleagues who work in building control. Mine is on a big concrete plinth so plenty of room around it, might be more by default than by design though.

Will get back to you on that one if OK!

Euan, I've 2 wood stoves and while the hearth extends 2ft (60cm) or more in front of one, I don't think it's quite as much for the other (btw both were installed by certified wood stove installer who was very well prepared re regulations i.e. chimney liner etc).

Both the stoves stand on legs well above the hearths (as does the stove in picture at top of this article). I've never known the hearth to be anything more than slightly warm, easily bearable to the hand. Reasons for this include the obvious (heat rises!) and my practice of keeping a decent bed of ashes under the fire which helps retain heat and direct it outwards / upwards.

I agree with your thoughts, sounds like yet another 'nanny state' job!

There's a lot of fear of house fires about. When we signed our lease, one of the conditions on it was that we wouldn't have any wood fires for heating and cooking. Some older chimneys have decayed a bit and would be unsafe to burn in without repair, some Victorian-era fireplaces were designed for coal not wood, and are quite shallow. So those could be reasons wood-burning gets banned in particular homes, but our unit doesn't even have a fireplace, which suggests it's a general ban rather than looking at the condition of each place...

Here Down Under house fires are started quite often because of electric heaters, people do things like put synthetic blankets over them, or stick them near curtains, the things short out and send sparks everywhere, and so on. So probably landlords and the various authorities imagine wood fires would be even more dangerous, thus various regulations.


The dimensions of the hearth are shown on Page 32 of the Building Regulations Part J

It's not quite so severe as 600mm, a minimum of 225mm for a closed stove, or 300mm for an open stove (or a closed one that is used in open mode).

Note that if you have an existing fireplace that the hearth should protrude at least 500mm from the existing chimney breast.

I met this requirement by using 600mm square stone effect slabs from the local DIY store.

These regulations have been derived over the years as the best practices to avoid the risk of fire. Having recently witnessed foam filled living room furniture burn (outside) - I now have a much greater respect for fire safety.


To all above posters- "nanny job"? WOW you cannot fart here in Oregon, (usa) without a permit.
Wood stoves must be UL listed, DEQ( department of environmental quality) approved, high efficiency types - old unapproved ones are illegal to install let alone sell even used.
36 " back space from a combustible wall. May be reduced to 18" with a masonry wall behind if it has a 1" airspace and holes near the base to allow air flow behind it. Clearance 18" from each side. Hearth area must be masonry or other "approved" "rated" material. All must be permitted and inspected.

Excellent article.
We will never achieve the level of independence the author has managed, due to our being old gits, but we are part way there and this writing encourages us to go further, Thanks

Thanks for the story, Andy. I might get to read the whole thing later on. (Busy Day)

Just wanted to mention, as regards a modest property-base, that a Permaculture fellow I spoke with last night says he can basically feed himself (Vegan) with what he grows on a quarter-acre, while he has 3 acres and is going to plant more of it for CSA and other sales/bartering.

The discussion (Oil Awareness Meetup in Portland, Maine) involved the UK Transition Town concept, and his slant on that was not to get 'too organized', hence homogenized into such an 'ism framework, but to let people find their niche' areas, and they would naturally develop networks with others to fill in the gaps in what they produced. That, anyway, has been his experience. Someone is raising chickens (many someones, probably), someone else angles towards tinctures, herbal medicines, etc.. someone keeps a Truck or Tractor that you can swap for services, etc.. He has grown Buckwheat, and discovered that the 'chaff' is highly valued by people growing Roses, and this scrap material goes for $30/bag.


That is really useful information. I can imagine that some specialization works best. This is all fascinating stuff. We are wrinklies just beginning to get the message in upstate NY and we've got a long way to go.

Karen -

I agree with you assessment of the situation in upstate NY. What are your experiences with building codes etc. ?

Here in the Hudson Valley I am continually astounded by the ease in which 5000 sq ft McMansions are approved and built. Yet try to build something less than 1000 sq ft or with some alternative building method (straw bale, yurts etc.) and you're put through the ringer to try to get approval.


An excellent description of your steps towards fossil fuel independence.

My partner and I are in a similar situation, a 1905 semi-detached house with 9" solid brick walls, and we re proceeding along the same lines to achieve some level of independence.

As you will be aware, it is a trade off between budget and what can practically be done within a property of such constructional constraints.

65% of the UK housing stock was built before 1960, and these traditional built houses are more likeky to have chimneys and the relative ease of converting to wood fired heating. For houses without a suitable flue, the expense of fitting one is likely to be the greatest deterrent to investing in wood heat. I suspect that only 20% of all UK households would choose to follow this route - despite the rising costs of domestic fuel.

Although we installed a condensing gas boiler and UFH in the summer of 2005, which slashed our gas consumption, we have subsequently installed a woodstove with back boiler, and this coming winter we expect to make the transition to wood-fired heating. We have retained the gas hob and oven, for convenience and these only amount to perhaps 5% of our overall gas usage.

We have held back on renovating the upstairs of the house, with the intention of adding 50mm of internal insulation (Celotex, Kingspan) to the external facing walls, plasterboarding and skimming with finishing coat. The upstairs ceilings will be similarly insulated.

We have halved our gas consumption from 28,000kWh in 2000/2001 and reduced the electricity consumption to 2800kWh - even though I work from home and run an office that uses about 2 - 3 kWh per day.

Not having to commute has saved a considerable amount of diesel mileage, and we do about 6000 miles per year, sharing the small car for short or economy trips and taking my van only when the nature of the load requires it - such as collecting firewood.

I have a 3kW Lister back-up generator, 108V 160h battery bank and 5kW inverter in my garden workshop, which runs on waste vegetable oil, but I am in the process of converting this to wood gas (from tree surgery waste) because of the transient nature of WVO.

I intend to install some pV in order to offset some of the power that my home-office consumes. This hopefully will result in a 25 to 30% reduction in power consumption from the grid. I will not be attempting to achieve grid tie, because of the current cost of the equipment and the poor rate offered for exported power.

The garden has seen some veg growing in previous years, and I have retained about 100' x 16' of garden for future veg plots, when I have more time to work on them.

Details of my approach are on my website at


65% of the UK housing stock was built before 1960, and these traditional built houses are more likely to have chimneys and the relative ease of converting to wood fired heating. For houses without a suitable flue, the expense of fitting one is likely to be the greatest deterrent to investing in wood heat. I suspect that only 20% of all UK households would choose to follow this route - despite the rising costs of domestic fuel.

I have an office in a separate building which does not have a chimney. Our local (fully registered) wood stove installer suggested an internal stainless steel chimney exiting either through a wall or through the roof (which here in Scotland is a slate roof). Cost including small wood stove around £3000 i.e. $6k. As I talked to installer a few months ago I'd work with £3500 now but that's not a huge issue if one expects (as most here do) big electricity price hikes in future years (I quote electricity as there's no mains gas here but all energy costs are pretty certain to rise).

How much experience is there with Listers running on wood gas?  I've been thinking about that but haven't seen anything definite.

Looking forward to playing with this myself.

Thanks for the article. It was very informative.

Our woodstove has the option of a clip-on back boiler, so I'd be interested in hearing everyone's views or experiences with them. I get the impression that they mightn't be the best thing for efficiency of burn, but that may not be the most important thing depending on the application.

As far as I am aware a stove with a back boiler is not as efficient as it can't achieve the same high burning temperatures as one without.

But if you want to heat a cylinder and radiators, nothing else will do unfortunately!

Excellent article by a thoughtful person trying to make the best of marginal situation. It very clearly illustrates the problems of retrofitting old dwellings. I was stunned by Andy's comment of being unable to insulate the wall cavities which I assume therefore must be masonry? The key to post peak oil housing is of course not just insulation but super insulation ideally placed OUTSIDE of thermal mass.Thermal mass is your friend if it's insulated and your implacable enemy if not. I would like Andy to explain why he cannot insulate his wall cavities because that seems like a fatal flaw of the building. IF he does not have masonry walls he should be able to insulate his walls. If not he should consider building a properly insulated internal wall system within his external walls. Since they would not need to be structural, the cost would be modest. Obviously he would lose some interior space. He might even just do this on the key areas he lives in like the LR and kitchen/bath and omit other rooms like the bedrooms which can be left uninsulated Another key concept is orientation of the long axis of the house due south. Perhaps he might consider a solar greenhouse on his south side which could contain a thick insulated solar slab which could store heat for days. We live in a frigid part of the United states and regularly see -30 to -40 every winter and have seen below -60 F. My solar room heats our log cabin on sunny days when it's not bitterly cold and is generally the most popular room in our house except in the summer when it is packed with growing vegetables.What on earth is a sustainability manager by the way?

Hi hugho,

The walls are solid brick (3 bricks thick) and as we are on the end of a row, we have a very large gable end wall facing East. However there are no windows in that wall.

I have toyed with the idea of internal dry lining for a bit of insulation, but to be absolutely blunt it just doesn't seem like it's worth the effort, we are always comfortable. I think one aspect of the thermal mass issue which is sometimes missed is that with a solid fuel stove, the flue gases are heating the mass of the chimney stack which is right in the middle of the house. This is very good as the chimney stack is about as insulated from the outside of the house as you can get, having the entire house in the way. But the chimney stack is thermally connected to all the outside walls of the house, so that even if you insulated a couple of rooms internally, it would probably have no real effect on how much heat is being lost overall, because the heat going through the radiators is only a relatively small proportion of the total heat in the house, unlike with a gas boiler, where the house used to go cold almost immediately upon turning the boiler off. Nowadays it takes the best part of a day to cool down.

Having lived in a 100 year old "Victorian" era house in Asheville NC, I can sympathize with the process of insulating and upgrading an old structure. Our house, fortunately, had framed wall cavities and a heavy pebble-dash stucco exterior, so we drilled holes from the interior for blowing in the insulation.

One point that many people forget, in tallying up the cost-effectiveness of such upgrading, is the comfort factor. Adding X amount of insulation to a house will not necessarily result in X amount of energy savings. Typically the result will be a combination of increased comfort + a certain energy savings. We had kept our thermostat (gas forced air heat, high efficiency gas furnace) at ~ 60F and wore the proverbial extra sweater. After insulation, 60F seemed warmer because the interior surfaces of the exterior walls were warmer and our bodies were not losing that radiant heat to cold walls. I would think that solid masonry walls would be a real negative in comfort given the amount of heat they would have to soak up before feeling warm to the radiating bodies inside the structure.


Thank you for a fascinating contribution.

One reservation:

Wood is cheap because fossil fuels are cheap (as bill h also points out). It’s a matter of scale. So don’t kid yourself: once the price of fossil fuels goes through the roof, the price of wood will follow suit, in line with exploding demand. Wood is fine as a backup in emergencies (such as power cuts) but it will not reduce your overall energy expenditure to any great extent either before or after TEOTWAWKI.

One question:

What percentage of your total annual electricity consumption is PV-generated? You say you use 3200 units of electricity annually (3200 kilowatt hours). Since you have currently 330 watts rated capacity PV installed and assuming 10% efficiency you can’t be getting more than 33 watts on average, thus 33*365*24 = 289080 = approx 290 kilowatt hours per annum. So your PV system is currently generating a maximum of 9% [290/3200] of your annual consumption. Is that right?

Hi CO,

Agree with your first comment 100%, I just like a log fire to be honest, it's just one of those eternal luxuries I think.

To your second question, which is a very good question. Unfortunately my inverter/charger doesn't measure kWh generated, it only shows the battery voltage which is a bit of a pain. The answer though is, not very much at the minute. After I had installed my 330Wp, I thought it wasn't performing that well, then I did the sums again and realised that the inverter itself is probably using up 100Wp+ of that just for running, it's pretty efficient but it's still on 24/7.

I can charge the batteries from the mains, what the remaining 230Wp does is basically stop the batteries running down as fast as they would without the PV charging them. In the winter the batteries will last 2-3 days without grid support running the stuff they do, in the summer they will last about 5-6 days I would say. That's 720Ah of batteries, half discharged (i.e. 100% discharged) would store about 8.5kWh if my maths is correct (please correct this if it's wrong). So if the batteries last about twice as long in the summer, that's about 8.5KWh over 5 or 6 days, say 10KWh per week in the summer. So on average probably about 5kWh per week, which is 260kWh in a year, or about 7.5% of my total consumption at a pure guess (remember total consumption is 3460 not 3200 because the 260 never gets near the meter).

Because the inverter is eating 100W+ of the PV, any extra I add should have a disproportionately large effect on the overall performance. I've got another 165Wp panel ready to go into the system and maybe if I get another 200W+ as a final panel, I should be getting somewhere.

The inverter/charger can take up to about 1kW of renewable power, so I could always even add a 300W wind turbine in there at some stage I suppose.

Although in financial payback terms the PV doesn't really look that great, it has added value, because it is connected into the 'off-grid' ring main, which runs the solar and central heating pump, all our lights and communications equipment like TV, internet, telephone etc etc as well as our fridge, microwave, mobile chargers etc etc during a power cut. This is something I keep trying to get across to people - energy security by rights should command a hefty premium, whether it's connected to the comfort value of having off-grid power for at least 3 days for essential heating, lighting and comms systems, and more when a) the sun is shining and b) the more PV I get - or in business, energy security is worth exactly what you would lose in business during a power cut, i.e. pretty close to the net worth of your business, multiplied by whatever outage risk percentage is appropriate.

I would hate to think of my solar hot water system sitting there baking in the sun doing nothing because the national grid had overloaded from air conditioning systems and couldn't run the 20W impeller pump. Hopefully if I can get enough PV, wind etc, then for a large chunk of the summer I could run my 'critical systems' completely off-grid, and in the winter I have 3 days of backup electricity in the batteries.

Apologies if the sums in this post are dodgy, they really are complete guesses! But you get the general idea anyway.

in the winter I have 3 days of backup electricity in the batteries.

It is a terrible shame that we don't have a market in e.g. air-cycle heat engines which run off wood stoves.  As long as you were burning wood for heat, you'd have electricity to run your circulation pump and probably quite a bit to spare.

Sounds good, but wouldn't the reduction in flue draught from the removal of energy from flue gases result in a lower burn efficiency for the stove?

I think you're right about wood and it's future price.

A clear example would be used cooking oil for biodiesel production. It may have been available free as waste a few years ago, but it didn't take very long for a market to develop once people realized its value. There are even stories about people stealing it now!

Wood cheap due to cheap fossil fuels?

Wood will always be cheaper energy than fossil fuels. As a (swedish) forest owner, I have looked at the farm bookkeeping and arrived at the following:

For the wood I have delivered as logs or as cut firewood by the roadside or at the farm center, roughly 1/3 being saw-mill timber or paper-mill timber, both fir and spruce, the rest being cut firewood with a mix of birch, aspen, ash, oak, fir, spruce, salix and several others I don't know the english translation of, I have burnt 1 kWh of gasoline or diesel or renewable hydro electricity (for firewood processing) for every 193 kWh of energy contained in all those logs or cut firewood. Now, 1/3 was delivered to mills and not used for energy, but I could have cut it up as firewood instead. This calculation was based on the actual energy content of dried firewood for each of the species mentioned above, in the correct delivered proportions.

On top of that I have a quite large heap of treetops and branches going to a biofuel co-generation plant, but that's not in fetched by the buer yet, so I don't know exactly how much energy it will turn out to be


If all that was delivered to locals, I would still be able to charge 1/100th the price of the energy in oil and still come out on top, disregarding my intention to get a salary and cover investments in forest and machinery... So I sell the firewood for roughly 1/5 the price of energy in diesel (which is heavily taxed here in Sweden). And even at that price, I've had to turn down customers in order to stack up reserves for fall or winter, when I can sell the firewood at higher prices to people who forgot to order in spring.

Yes, firewood will increase in price as the price of fuel goes up. But it will always make both economic and energy sense to produce firewood from fossile fuels, no matter what the cost.

And yes, there is energy in the macinery and my own food too, but I'm guessing that the EROEI of firewood still is above 1:100. And some of that energy was renewable electricity to start with.

Now even if corn-based ethanol would have an EROEI of 10:1 (which it doesn't, it's better), it still would make sense to use that ethanol in my chainsaw and forest machine, the system EROEI of the firewood would still be 1:19.3 (or 1:10 if my estimate for the machinery and my own food was correct).

Firewood is so cheap to produce energy-wise, that any kind of synthetic crap energy still would make sense to use for firewood production.

Just too bad there aren't enough forests for all people on the planet. At least not if they wan't to have paper and timber too.

I think the 3 day backup idea is excellent and if adopted by millions of homes it could be a form of large scale energy storage ...'distributed microstorage'. It may also reduce the vulnerability of transmission lines because of multiple connections.

If you were to get say an electric scooter you will require more panels with possible upgrades to ancillary equipment. You would then have to solve conflicts between wood smoke and insolation. I'd guess firewood is expensive in the UK so sawdust briquettes or other biomass could be more sustainable.

The figures they give for some of the Ultra Motor bikes are that they only use around 250watts for 30 miles.
Ultra Motor

As far as I can see they are not available yet in the UK, but presumably other bikes are similar in their modest power consumption.

Dave I run one of the Ezee Qaundo electric fold-ups. It has a 30km range with a 30kmh top speed ( or more if you pedal like a nutter ).
It's hilarious shooting pas the lycra crowd uphill on a crappy shopper bike with giant basket full of tinnies :)
Add more batteries for more range etc.
Altought the UK importers are currently having fun renegotiating their sole status with the manufacturer there are plenty of choices available :

I'm a bit fat and old to pedal - on an electric bike I will look like a cherry on a cocktail stick! Have you any idea of any decent folding bikes with powerful motors?
I live on the second floor in a flat, so need to haul it upstairs, but I don't need to go far - I will probably keep my car for occasional use anyway, but dapping off to the shops could easily be done on a bike.

This has pedals but also a full twist grip throttle. Pedalling is purely optional !
It weighs 25kg ... all electrics weigh a good bit more than the equivalent conventional bike. If you want very light and folding then there are converted Bromptons around. is a good forum and resource.

Cheers. I think I will hang on for a purpose-built bike or perhaps even get a non-folding one - folding is, perhaps most useful for putting it in the car, whereas maybe it would be easier for me to bump it up the stairs unfolded.

Pedalling won't do much for the age, but it'll help with the fat :)

Yeah, but stopping breathing is so darn inconvenient! :-0
That is the great thing about electric bikes, it means that for those of us for whom bikes would be wholly impractical, we could still get out of our cars - although I will have to do a test run with a friend's bike first, to see if I can manage at all to get it up the stairs to my flat.

There seems to be this strange idea that if you're on your bike, you must pedal at the greatest rate physically possible, and thus must wear "bike clothes". Sort of the equivalent of pedestrians all decked out like Ben Johnson and sprinting everywhere.

Why? It's just another way of commuting, take it easy. Check out copenhagenize, lots of pictures from a city where a third of all trips taken are by bicycle. People are in suits and dresses and jeans - it's just a way of getting around, not an athletic endeavour.

If you are relatively fit it is easy not to make enough allowance for what people who aren't can do.
This is by no means peculiar to myself.
Some people can't manage a bike. particularly in hilly areas like Bristol, however much it may seem to you that they should be able to. Most people, in consultation with their doctors, are the best judge of their own health and capabilities
Copenhagen is flat, if you look very carefully at the pictures!
People get older, and they suffer health issues.

There's no way I could ever get enough PV to charge an electric scooter - this is just a terraced house, remember, I will be lucky to get enough PV to run my basic systems excluding cooking and washing.

What I always say to people about renewables is that compared to fossil fuels they are crap - but compared to having no electricity at all they are amazing. You have to get things in perspective.

About the 3-day backup, I'm not altogether happy about it as I'm not sure what the resource implications of fitting every house with its own backup battery bank would be. Only the other day my dad was asking me about batteries, prices and how long they last etc. If everyone did it, I'm not sure what it would do to the price of lead, sulphuric acid etc.

Then again, the practice might eventually attract better electricity tariffs from the national grid - if you buy batteries, you are basically putting your own money on the line to help the NG balance supply and demand, which in a situation of decreasing reliability, could be worth a lot . . .

I suppose balance is the watchword really.

I think the 3 day backup idea is excellent and if adopted by millions of homes it could be a form of large scale energy storage ...'distributed microstorage'.

Bingo! I think microstorage is more useful/suitable than microgeneration for the problems the UK faces over the coming decade. Having a 'critical' circuit in the house with battery backup (PV etc not needed, charge from grid) would make a massive difference in a future of unreliable grid supply.

The questions for battery-to-grid are
1) how much is needed?
2) where will the money come from?

For example an aged pensioner may have an easily fitted roof but no spare cash to take advantage of solar grants or feed-in tariffs. We need a new financing model that covers cost sharing, battery replacement, power company profits, demand shifting, smart meters and so forth. I think it could make nuclear seem cheap by comparison.


I also think distributed microstorage is a good idea.

One advantage would be that it would allow greater use of wind turbines and other peaky renewables to supplement the existing grid, without having to employ vast amounts of costly diesel based reserve generating capacity.

To make this happen, you would need a large number of homes or commercial premises to be fitted with battery banks and grid exporting inverters.

Lead acid batteries are currently priced at around £100 per kWh storage, and suitable grid tied inverters priced at around £500 per kW. So a 10kWh storage capacity and 3kW peak output would be around £2500. This would be paid for by a greatly discounted tariff from the electricity supplier, or by shared ownership with the utility.

The key to making it work would be dynamic demand management and control.

Dynamic Demand Info

When the grid is supplying more than the current demand, the frequency rises above 50Hz. A simple 50 cent microcontroller, plugged into any ac socket can measure the grid frequency accurately - which is uniform across the whole nation. A frequency greater than 50Hz is the signal to the microstorage system to enter its charging mode, and consume the surplus power from the grid, helping to restore the frequency to 50Hz.

At times of peak demand, the grid frequency will drop below 50Hz, and this would prompt the microstorage systems to export to the grid, thus restoring the supply.

The microcontroller would be able to detect undervoltage and underfrequency drop-outs that are characteristic of imminent grid failures. The microstorage system would effectively work as a wholehouse UPS, protecting the electrical and consumer equipment from powercuts and surges.

The National Grid in the UK has to handle 2:1 demand swings between about 30GW and 65GW in winter and 22GW to 45GW in summer. This process needs to be carefully managed to make sure there is sufficient spinning reserve capacity available to meet the peak demand. This reserve capacity is usually provided by costly diesel generator systems, which can be started quickly to maintain supply. At times of extreme grid imbalance, non-critical loads such as furnaces electrolysis plants and steel rolling mills can be disconnected to reduce the load.

Microstorage could eliminate some of this diesel based reserve capacity, and also allow better load balancing from wind turbines and other peaky renewables such as wave, solar and tidal power.

Real time data for grid frequency and instantaneous demand can be found on the National Grid Company site.

Realtime Info

The microstorage would be sized to provide sufficient backup for a household at the mean consumption rate. For example, if I use 8kWh per day at home, I might choose a 2 day or a 3 day battery capacity.

The power companies would benefit from improved load balancing and the ability to reduce costly contracts for maintained spinning reserves.

Once having installed a microstorage system, you are then in a position to add your own renewable or microgeneration equipment.

If the microstorage system just happened to be based around the battery system of your electric car, typically being recharged at night, then this might be another interesting way to introduce this technology.

Dynamic demand control can also be applied to heating and air-conditioning equipment, to maintain efficient grid balancing, even at times of peak demand.

Fortunately in the UK we have not yet reached the point of needing domestic air conditioning.


Good to hear others agree. The trouble is my back of the envelope calculations came up with trillions in costs once you add in PV panels. In Australian heatwaves (>40C) you could need 2kw per person for air conditioning hours at a stretch.

What prompted me to think this way is that I had to get a UPS when the grid here in Tasmania went from nearly all hydro to heavily coal fired via an HVDC cable. Brief blackouts started occurring. The cheap UPS I use is only good for blackouts not partial signal restoration during brownouts. I also have a lead acid battery on a solar pond pump which has worked flawlessly for years. Simple but it works.

Have you looked at using an air heat pump as part of the system? That should reduce costs a lot, although PV costs have to fall a long way too.
The trouble is that a lot of houses are built on the assumption of cheap power, so really are not adapted to the climate, even in simple ways like painting them white, traditional in hot areas.
Greenroof technology or mud and straw walls would also vastly reduce the energy requirements - I remember seeing on the TV documentaries about underground dwellings in the desert of Australia.
Decent design I would have imagined would also include provision for storage of rainwater, and perhaps greywater, which could act as a heat store.
All of that, except the white paint, takes time though!

I've solved the summer heat problem through passive cooling. It only gets to 37C at my place. I do have a 50,000L water tank and a potato cellar so I may be able to use them as ground sources if the summers get hotter.

Some interstate friends are saying no to air conditioning and toughing out shade temperatures of 44C every summer. When all the millions of baby boomers are in nursing homes there will have to be a low energy solution.

As for dugouts here's a little known factoid; some workers at the world's largest uranium mine Olympic Dam choose not to live in air conditioned bungalows nearby but to commute 35km to dugouts in an old mining settlement.

Studies have shown that dishwashers make more efficient use of water and electricity than washing up by hand ...

Besides being more efficient, dishwashers are also much more sanitary. My wife and I shudder at the horrible sanitary conditions we run into at many "permaculture" events. But it's useless explaining the efficiency and safety aspects of a dishwasher to adepts of the church of permaculture. Anyway, for the great article on your remodel, and I'm sure you will enjoy the benefits for many years.

Actually, even more recent studies have suggested that the previous studies were commissioned by companies trying to sell dishwashers.

I can believe that dishwashers are more water efficient than washing dishes by hand, not so sure about energy efficient though.

I think the jury might still be out on that one. But one thing's for sure - it's one of the best kitchen appliances ever invented!!

In terms of water use, given the amount of dishes done in an average home, the most efficient machine uses less water than the least efficient person. But the average machine uses several times more water than the average machine.

Where the machine is definitely better in water use is with large volumes of dishes, as in a restaurant. If a restaurant seats 40 it might serve 200 customers a day, which means 200 large plates, 100 small plates, 100 bowls, 200 glasses, and about 1,000 pieces of cutlery, all over 10 hours. That volume of dishes, a machine is more efficient than a person.

But at home with at most a dozen or two dishes a day, a person is usually more efficient in water use.

Of course, another aspect of water use is sewage treatment. It takes a lot of water to process your wastewater going down the drain. For example, here in Australia in 2001 it was found that about 7% of all fresh water used was for water treatment (though the figure also include some evapouration). The more nasty stuff you put in the water, the more water they need to clean it up.

The pellets they put in dishwashers are caustic, they're pretty nasty. If the system just has to process dishwater with some grease and liquid soap, that's not much water compared to processing it with caustic substances in it. So even if the machines always used less water than people in the dishwashing, they'd still use more water in cleaning up the wastewater afterwards.

In terms of energy use, doing it by hand is the clear winner in every case. The machine has water at a higher temperature, and pushes that water around with electric pumps.

Lastly, there is the water and energy use of the manufacture of the machines. Typically the machine has 500kg or so of greenhouse gas emissions associated with its manufacture.

Not true re: water use. Dishwashers are the way to go if you comply with two simple criteria. Run a dishwasher only when it’s full, and don’t rinse your dishes before putting them in the dishwasher.

Handwashing fails the sewage treatment test, requiring 6 times more water than a dishwasher, and also more soap. With a small effort it is possible to find bio-friendly dishwasher cleaners that are no worse than hand washing detergent.

If you consider the energy used to heat the water used in handwashing, dishwashers come out ahead, refer to the University of Bonn study for more info.

Here's a link to the an article "Are Dishwashers Good for the Environment?" for more info.

Hand washing is notoriously unclean. I'll accept some risk in GHG emissions to protect my health.

The study reports on,

12 place settings of dishes (140 individual parts including crockery, glasses and cutlery)

I specifically said,

Where the machine is definitely better in water use is with large volumes of dishes, as in a restaurant.

A "12 place setting" means 12 sets of dishes - 12 plates, 12 small plates, 12 bowls, etc. If you're doing a large amount of dishes, then a machine is more efficient. If you're doing a regular household amount of dishes, then that's rather different.

The Bonn eggheads say,

Assuming in a private household the amount of dishes used in our test is representative for the amount if dishes washed per day,

I imagine they must have housekeepers, because very few households do that many dishes each day. Most people have a 4-set of dishes, that's how they're sold and people use them. A 4-set is quite sufficient for the average 2.6 person household's lunch and dinner each day. That's a third as many dishes as the eggheads at Bonn suppose. Their assumption is wrong.

Sewage treatment is not difficult in proportion to the volume of water to be treated, but in proportion to the absolute amount of non-water substances to be removed. However many litres of water with 100ml of regular liquid detergent requires less treatment than however many litres of water with 100g of machine powder, which is extremely caustic (see the warning labels).

Cleanliness in the Bonn study is reported to be better for machines than for people, however they nowhere tell us the criteria on which they judge cleanliness. Spots left? Greasy feel? Swabs taken for agar plates and bacteria grown over 7 days? They don't say.

Again: the most efficient machines are better than the least efficient people for any number of dishes; the most efficient machines are better than the average person for a large number of dishes.

The study I looked at was done by the University of Bonn and was NOT commissioned by companies trying to sell dishwashers. The study found that a dishwasher (a modern energy efficient model) uses only half the energy, one-sixth of the water, and less soap than hand-washing an identical set of dirty dishes. The study also found that dishwashers excelled in cleanliness over hand washing.

Fantastic - thanks for the reference Liferaft, I feel much better now!

The link you provided is to "the works of m. meo", who is apparently some kind of mathematics teacher. It's unclear what this is supposed to have to do with washing dishes.

Sorry, sometimes when you give links people will actually go and look at them rather than just accepting whatever you say :)

Ahaa!! The debate rages on . . . :-)

Interesting that you are using boat technology in Bury!

I lived on a boat for 2 years, sailing from UK to Oz. The ritual of leaving a dock was started by reeling in the hose, so we became reliant on our own water (desalinator) and then cutting the power. Actually undoing the lines was the last step. But it was disconnecting from shore power that had a very symbolic feel about it.

We had a wind generator (400W), a water generator (400W) and 500W of solar panels. We also had a 4kW alternator on the main engine and a 3kW genset. Needless to say diesel was the main power source. I like sailing with cold beer! I also dislike steering and the autopilot was hydraulic and could draw up to 30Amps at 24V. The desalinator drew 10 Amps (about 4W per litre fresh water produced) and could run off wind and solar provided we were anchored far out in the windy part of the anchorage. If we wanted to anchor in the sheltered part of the anchorage, we had to use the genset.

Little did I know in 2003 that this would be a metaphor for the choices we face barely 5 years on.

So it's WOOD --> WHALE BLUBBER --> COAL --> OIL ---> WOOD? I don't think so.

The thing I hate about living in a city are the thoughtless neighbours who insist on using "cosy" wood fires to heat their houses, sending copious amounts of carcinogenic gasses into the windows of all nearby. It should be banned.

Burning wood should not be banned. Inefficient stoves that does not fully combust should. With a modern boiler achieving over 90% efficiency you don't get any of those nasty gases from your chimney.

There is at least one study here in Sweden arriving at the conclusion that members of households that burn wood for heating live longer. This is supposedly due to anti-oxidants produced by the firewood.

I haven't read the study, so I cannot tell if they've checked so it's not due to the excercise from hauling wood and all the clean air most wood-burning households have here in Sweden, as they are mostly located in the countryside.

One known drawback from firewood is "firewood-disease", if you contract any fungi from improperly dried firewood.

Ever visited a coal-fired station? Plenty of stinky soot from those buggers, too.

The difference between the two is whether the filth is in your backyard, or someone else's backyard.

Ideally there is no filth anywhere, but it seems that protests against sooty fireplaces are rather louder than protests against sooty coal-fired stations...

If you want to burn wood in a smoke control area, you need to use a stove which has been tested for particulate emissions by DEFRA and exempted from the Clean Air Act. You can find a list of these appliances here:-

As for toxic gases, I think you'll find that NOx emissions are actually lower from clean burning wood stoves than they are from gas boilers. So if you want to be a good neighbour and get rid of your toxic home heating, you'd better get rid of your gas boiler and go for wood or a heat pump or something.

You know not whereof you speak. See below.

The largest single source of outdoor fine particles (PM2.5) entering into our homes in many American cities is our neighbor's fireplace or wood stove. Despite the ineffectiveness of a fireplace in heating a home, only a few hours of wood burning in a single home at night can raise fine particle concentrations in dozens of surrounding homes throughout the neighborhood and cause PAH concentrations higher than 2,000 ng/m3. The far reaching implications of these scientific discoveries for environmental laws have not yet sunk in the Nation's consciousness. The best way to reduce the exposures of our children and families to toxic pollutants that cause cancer, asthma, or other diseases is by taking very simple steps in our daily lives, not relying on billion-dollar "remediations" or complex laws controlling industrial point source emissions. Indeed, ignoring indoor air pollution and human exposure as the nation is doing under its current environmental laws, is a tragic disregard of our children's health and the well-being of future generations." ( Dr. Wayne Ott, Statistics, Stanford University, 2/1/98)

More facts about the wonder of wood burning fires can be read here.

You really don't want to see any solutions, only problems, do you?

Society of fear?

Could someone please point out which 60 000 US residents died of wood smoke?

And could somone please point out which US residents were killed by fossil fuel emissions and fossil fuel driven traffic?

Go ban the car while you're at it. People die from traffic you know. Car accidents.

To put a little fear of God into you, whenever you're walking on the sidewalk you're seconds from death; all it takes is a small verve from one of the passing cars and you're dead. Better stay indoors.

Perhaps you imagine the soot from coal-fired stations has vitamin C?

If we burn stuff to keep warm and cook, then the air will be poisoned. It's just a matter of whether the air is poisoned in your backyard, or someone else's.

For my part, I am in favour of solutions where the nasty consequences are local. I should not be able to dump my mess in someone else's lap, but should have to figure out ways of cleaning it up myself.

Wood stoves linked to mouth cancer. Thursday January 21 8:07 PM ET NEW YORK, Jan 21 (Reuters Health) -- Wood burning stoves appear to increase the risk of cancers of the mouth and throat, a study suggests. People exposed to the smoke from such stoves have 2 to 3 times the risk of cancers of the mouth and throat, and the wood stoves may be responsible for 30% of all such cancers, according to the study conducted of 2,352 people living in Southern Brazil. ``Cooking and heating stoves are used in more than half the world's households and have been shown in many locations to produce high indoor concentrations of particulates, carbon monoxide and other combustion-related pollutants,'' reported Dr. Eduardo Franco, of McGill University, Montreal, Canada, and colleagues in the International Journal of Epidemiology. ``Wood and coal fires generate a number of combustion products which are known, or suspected carcinogenic agents.'' Franco, along with Brazilian colleagues, compared 784 patients with mouth and throat cancers to 1,568 people without cancer. Of the cancer patients, about 48% had mouth cancer, 27% had pharyngeal cancer and 25% had laryngeal cancer. After taking into account tobacco and alcohol consumption, which increase the risk of such cancers, particularly when consumed together, the researchers found that the use of a wood stove was still linked to increased cancer risk. The women in the study appeared to be at greater risk for the cancer, particularly cancer of the larynx. ``This finding is probably related to the fact that women are more exposed to emissions from wood stoves,'' the authors note. ``Analogous results were found in China, where women exposed to emissions from cooking stoves were at higher risk of developing lung cancer than men.''(International Journal of Epidemiology 1998; 27:936-940)

I think that some of the comments above have been made without a full understanding of the various combustion methods studied.

There is absolutely no question that if you are cooking over an open wood fire or basic non-enclosed woodstove, or barbeque that you will be exposed to higher levels of particulates, tar compounds and increased levels of carbon monoxide.

However, many of these developing country stoves were badly designed and are located in poorly ventilated rooms without an adequate length of flue to provide ample draught.

Even in relatively well developed countries, the use of outdoor boilers, can lead to excess quantities of woodsmoke. This occurs either because of poor design, incomplete combustion, inadequate draught or lack of knowledge in how to prepare the wood, ensure the correct moisture level and achieve the correct temperatures within the stove to eliminate the smoke.

Woodsmoke is the first sign of inefficient or incomplete combustion.

There has been considerable research done on improving the efficiency of woodstoves both for developing countries and the western world, such that the emissions are minimised.

Many new designs make use of a 2 stage burn, where the primary combustion generates woodgas, by the action of pyrolisis (gasification) and then this woodgas is burned cleanly at high temperature with the correct quantity of pre-heated air to ensure complete combustion and consumation of the particulates and tars.

Wood fired heating in a modern well designed enclosed stove will produce minimum of emissions. It is essential to use well seasoned firewood to achieve the high combustion temperatures needed.

Most western countries use a stove certification system to ensure that new stoves meet the minimum emission standards.

For those prepared to follow this route, I believe wood fired heating forms a legitimate means to reduce one's dependence on fossil fuels, and is an effective means to personal energy security.


Thanks for this post and the comments, some thoughts, hints, advice.

I am at present refurbishing a tiny country house, 100 yrs old at least, and one very vexing point is insulation (interior or exterior) of the walls, which are stone and more than 25 cms thick. I know the house, have felt and lived, of course that is in particular conditions, with heat of that or that type, etc. (Switzerland in the valley, at 400 m., continental mid EU climate.)

I have heard about 15 expert, sometimes paid for, different opinions, all of them contradictory. I am lost. Googling and libraries haven’t helped at all.

Finally, finance will win out, anything that was proposed is beyond my budget. I sort of am giving up on it. The house will have double and some triple glazed windows, traditional wooden shutters (mandatory), inside curtains - da best by my hand. That is it. But really, I couldn’t educate myself on this...which surprised me. The best info I found, surprisingly, came from French deco and brico magazines, which I had never looked at before. Huh, at my level of understanding.

The basic problem is that you have to trade space for insulation.
25cm is not that thick for stone built - I have worked on stone houses where the walls were 75cm thick.
If the rooms are tiny the best answer would probably be to build a new wall on the outside, and put insulation in between that and the inner wall.
I doubt either finances or planning permission would allow that.
Information is up-thread on building an inner-wall (I used to be a builder, but at the time there was no call to do super-insulation, hence my somewhat naive questions up-thread - you know want you know, and shouldn't jump to conclusions)
I doubt that you have the room to do much in the way of putting in inner walls and insulation- it is not that expensive.
So can anything be done? You betcha!
You haven't mentioned the roof space - you want to go to town on insulating that, possibly if you want to use a lot of the attic floor by using one of the systems I have linked to above to put insulation directly beneath the tiles.
The next thing to consider is that it makes quite a difference to have even one worm room in the house - that is all we had when I was a boy - you just hurried into bed in the bedroom and wore nightclothes.
So for your one warm room you might consider this:
It costs around $5sq ft, so it is by no means cheap, but on the outside wall it may be do-able (don't forget a damp-proof membrane) and you will need plasterboard.
It insulates 37 times better than rockwool, so you won't cut a lot into your room, other than for the plasterboard.
So for the aerogel, if you have a 5 meter by 2.5 meter exterior wall, you might need around $625, although I am not entirely clear if that is a retail price or wholesale.
You would still have to pay for the membrane, plasterboard and installation, but if you just gradually work round the exterior walls it should be do-able.
Don't forget to insulate the reveals and so on.
Hope this helps,

There are also foil-based insulation that claims high insulation values for minimal thicknesses. I'm not a builder, but I think they get used in tricky situations such as domes or in between rafters to be left exposed in old cottages etc. That's what it said on the "Grand Designs" tv program anyway.

A little google suggests they may not be all they claim however.

There is a nanotech paint called Nansulate by Industrial Nanotech.I've used it in my house built in 1927 with no side wall insulation.You would want to use the Home protect clear coat.I'm about 60% done on the inside and have dropped our utilities about 30% Nansulate has the EU approvial.It's a water base coating and can be painted if desired 2 days later I recomend the clear coat because it has twice the insulating power as the tintable.I'm coating my bare basement walls and rim joist next.

The insulation value of this paint is very low. From memory, vaporlock or other company representative has come on TOD to tout their product before.

After extended discussion on TOD, the consensus is that insulating paint has marginal utility in some very few specialty applications.


Solar bud,

Thanks for your reply to my earlier posting. As regards PV's potential, you might find the following arguments made by George Monbiot to be of interest:

In his book Half Gone, Jeremy Leggett, the chief executive of Solar Century, claims that “even in the cloudy UK, more electricity than the nation currently uses could be generated by putting PV roof tiles on all suitable roofs.”(5) This is a big claim, so you would expect it to come from a good source: a peer-reviewed journal, perhaps. Here is the reference Leggett gives: “‘Solar Energy: brilliantly simple’, BP pamphlet, available on UK petrol forecourts”(6).

The Energy Technology Support Unit (now Future Energy Solutions ) calculated that if solar electricity could somehow achieve an efficiency of 12-15% at all points of the compass, the “maximum practicable resource” in 2025 would be 266 terawatt hours (TWh) per year(7). Total electricity demand in the UK is currently 407TWh(8). But Leggett’s claim is far more misleading than this suggests.

The first reason is that solar panels facing north are less efficient than solar panels facing south. The second is that seeking to generate all our electricity by this means would be staggeringly and pointlessly expensive – there are far better ways of spending the same money. The International Energy Agency’s MARKAL model gives a cost per tonne of carbon saved by solar electricity in 2020 of between £2200 and £3300. Onshore macro wind power, by contrast, varies between a saving of £40 and a cost of £130 a tonne(9).

The third problem is that the supply of solar electricity is poorly matched to demand. In the UK, demand peaks on winter evenings. Even if we could produce 407TWh a year from solar panels on our roofs, only some of it could be used. There would be a surge of production in the summer, during the middle of the day, and very little in the winter. While solar panels might reasonably supply 5-10% of our electricity, the size and inefficiency of the energy storage and standby power system required makes a purely solar network impossible.

Source: 'Small is useless'

So don't say you haven't been warned!

Thanks CO, as a user of solar PV I am very much aware of its limitations; I have never suggested that it is a panacea but I do believe it has its place and a role to play.

I wanted some renewable electricity generation to go with my battery back-up system. A wind turbine isn't really a feasible proposition for me - although a lot cheaper than solar PV, I live in a very built-up area which is not well suited to wind. Such an appliance would also be relatively easily stolen, compared to PV panels which the would-be thief would have to risk life and limb to try to get off the house.

I don't think anyone seriously believes that solar PV can solve all our problems, but as received wisdom tells us that a mix of energy generating technologies is desirable, I do think it has a part to play, and in my own case is probably the best renewable electricity technology for my situation.

(no reply button so am just posting at the end)

Most of the walls are considerably more than 25 cms, up to 50 cms - but in one spot 25 cms...a sort of addition (built in 1920 0r so.) I can do nothing to the outside except cosmetic or ‘necessary repairs’. The roof will be new, and above ‘code’, ‘standard’ - very stiff in Switz...To Town and more. Thanks for all the pointers - I will look all up, but here as everywhere, there are habits, only so many choices, etc. The one warm room is already planned.

What I did not mention is that heating and hot water will come from a communal wood/bio mass plant.

A Sydney couple converted their terrace house in the inner-city suburb of Chippendale into a "sustainable house" and wrote a book about it: Sustainable house: living for our future by Michael Mobbs ISBN 094727748X. "Apart from food and clothing, our fundamental needs for life are water, waste water that can be re-used, and energy; we have almost met those needs from our own resources on this site." (p.13)