Wood for Heating: Is it Good, Clean, Sustainable, What’s it Like?

Let me get straight to the point: using wood is not a fossil fuel and can be carbon neutral because the tree it comes from took in the carbon before it gave it out when burnt. 

But yes, it being a sustainable and clean fuel depends on a few crucial things: the forests that the wood comes from must be managed well, the wood must be dried before burning which takes about two years just leaving it in an airy location, and the stoves and the chimneys must be of the kind that minimise the smoke and the particulates that are harmful.

All the processes and transport necessary to cut, sort, and deliver logs may not run on sustainable fuel of course, but this is nitpicking. In the best case, despite the small amount of pollution that occurs, which is unavoidable to some extent, burning wood is much better for the environment than using other sources of energy for heat, and to repeat, it does not contribute so much to climate heating. The increasing forest fires due to climate heating caused by burning fossil fuels is a far bigger source of particulate pollution, or smoke. Ironically, if this wild wood had been destined for heating homes in wood burning stoves these forests might have been managed better and therefore prevented the wildfires in the first place.

There are other technologies that can come into play with using wood as fuel. Pyrolytic converters can burn and convert wood into wood gas that can function as a fuel even in conventional internal combustion engines. Wood can also be made into a liquid fuel. We will ignore these usages here, but they do have some potential I think. The main thing to remember is that the current priority is trying to reduce climate heating effects, not get a totally perfect fuel source.

Wood as a fuel has been criticized in the press, however.

For instance, in the Guardian, George Monbiot has thoroughly denounced his installation of a wood burning fire in his well-insulated home. It seemed like he was almost going to kill himself with the fire. But this was mainly because he did not make allowance for it to get enough fresh air. I suggest these kinds of articles are just subtle help to the fossil fuel industry, an attempt to ‘balance’ the narrative when there is no balance.

But for the sake of safety, let us look at what you need to do to successfully use a wood burning stove. It is not all plain sailing.

By stove I mean a metal enclosed log burner with a stainless-steel chimney that goes up through the roof, usually via an existing brick-built chimney. Some wood stoves allow you to cook on them, some do not provide a surface for this; some stoves use pellets of wood, but this requires extra processing of the wood that may not be sustainable and of course you pay for this, and also you cannot usually just sort of chuck on a log from the garden on them. But they can make the fire last longer using a hopper system.

Firstly, and most importantly, what you must have if you are to stay alive while using a log burner is a source of fresh air to the stove. If your house is insulated so well that all draughts of air have been prevented, you will probably stifle any log burning fire and cause yourself to die from carbon monoxide poisoning, because the fire will use up all the existing oxygen in your home, which you also need to breathe.

Modern insulated and double-glazed houses might have an air supply problem for fires, but older houses tend to have open chimneys and imperfectly fitting doors and windows that allow in fresh air; the problem is that obviously this air can be cold, and it will push out the warm air making you colder. An efficient wood burning stove can quickly use this air and turn it into heat, so this may not matter in an old house, but still, especially these days of the cost of living crisis, you will probably want to keep all the heat that you can in the house to reduce costs. All other forms of heating in my experience are more expensive.

For safety, it might be necessary to rig up a ventilation system especially for your fire. This can be as simple as installing an air vent near to or a small pipe directly into the stove. You could make this closable manually by the user, but for safety it would be better if it were at least partially passive and permanent. There are existing ventilation systems, ducting, which will exchange the air and keep it warm, but these tend to be more expensive and complicated and can require electricity. But remember, you will need ventilation if you are in a well-insulated house.

What do we do? In our old French stone house I have been installing some wooden double-glazing which has made it more air-tight, but it has open chimneys and some passive air vents so I am not worried. We get logs delivered and we use them usually only in one or two stoves, although we have more in different rooms. We also have a mini split ductless air conditioner (they are often called heat pumps but if they are reversible they can also supply cooling), plus some electric radiators that we rarely use but are there in case we go away and need to keep some heat on (such as to stop the water pipes from freezing in winter).

We rarely need to use the air conditioning for cooling, but it has been great on a couple of occasions recently when it was extremely hot. We do not use it when the wood stoves are burning because no matter how efficient your wood stove is, it will produce some smoke and therefore sooty deposits, especially on start up for the first time in the year, and this is not good for the heat pump.

Of course, there are drawbacks of burning wood and they need to be considered if you are thinking of going this route.

One is that it produces ash as a byproduct. We use this on the garden and put it on the compost heap, so it is ok and even a benefit, but it is a chore, and the fires need maintenance, and cleaning, and tend to be dirtier than other heating systems. The fire will last if we go out for a day but any longer it will go out. This can be irritating. It needs tending, stoking, and feeding.

Wood stoves can be temperamental, they respond to the weather and air pressure, sometimes it can be a devil to get the fire going, especially if the chimney has not been used for a while and if it has been cold and wet weather, it all needs to dry out and heat up. This difficulty is common on starting up the fire but if it persists you may have a blockage or not enough air. Because of this problem, I start a little fire in the stove occasionally, even in the summer when I do not need it, because this will help keep the chimney dry and discourage birds and bats from nesting in it and blocking it.

It is worth bearing in mind that houses can be fickle, some have wood stoves in them that never seem to heat well, for reasons unknown. It is hard to assess a house for this without actually installing a stove, unfortunately. Our house seems to work well with a log burner, but it is old and designed for it I suppose.

Sometimes you might need to put this special chemical stuff on the fire when burning, or special logs, which clean the chimney pipe, making the soot and tar come off and fall down, but you might still need to dismantle the pipes to empty and clean them out, maybe once a year, and this can be a pain and it gets you dirty.

We installed a double skinned stainless steel flexible pipe that keeps the fire hot all the way up the chimney, reducing smoke, so we have few problems with soot, but it was expensive, more than the stove in fact.

Oh, I need to use an axe sometimes to split the bigger logs, very macho but you get more heat with more surface area on the logs, the downside is that it burns quicker so you use the big logs to last the night. You need a place to do this chopping, and this can lead to wood chips going all over, quite messy. Logs have bark which flakes off everywhere, and of course you must get the logs to the stove somehow, and they can be heavy. You will be going in and out often. In the house you will need a place near the fire to stack them, but not too near because this would be a fire hazard. This place will get dirty with bits of sawdust and bark that always needs brushing. I also use a big bowsaw with an ‘americaine’ sawblade which is good for cutting logs, you need this because sometimes the logs are a bit too long to get in the fire. You need the biggest heaviest axe and the biggest bowsaw that you can get, this makes life easier.

Personally, I quite like doing all this work, but sometimes when it is early in the morning and it’s frosty and dark outside (ah yes you need exterior lighting) and I need to get the logs in, it is horrible; I have to put on some old coat that does not matter if it gets dirty; I always forget gloves, and if it is raining, ugh. I used to have a log basket that could carry about four, but it eventually broke, so I just carry them, but it means more trips, and opening and closing the door repeatedly lets out the heat. All this might help keep me fit perhaps but as I get older this is not going to be as easy.

Nevertheless, I love looking at a real fire, it is so restful and seems to somehow be better as heat than any other kind. There is something almost primeval about watching the flames, much better than doomscrolling your mobile or watching TV. And it is cheap as a fuel, relatively. We live, however, in a rural forested area of France where wood heating is normal. Here, it is sold by the ‘stere’ which is about a square meter in stacked logs. We get 500cm logs that just fit the stoves.

But, yes, there are dirty jobs to do with a wood fire and it requires some tools, space, and some basic skills, and it is not a perfect fuel, you do get some smoke and soot even when doing it all properly. But it is not adding to the climate emergency as much as the other fuel sources, and every energy source has drawbacks.

You will already know that not only does burning oil cause climate heating it also has a by product which is cheaply produced plastic that is polluting the environment. Oil has been great for humanity in the past, it has to be said, it has made our great advances as a species possible, but now it is having some dangerous outcomes and using wood for heating is a small way to counteract this.