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.