The most common mistake is to get too large a stove. Wood burners work best if they are burning dry wood vigorously – smouldering wood leads to tarred up chimneys (eventually chimney fires) and smoke that will annoy the neighbours. A large wood burner can emit more than 6kw which would rapidly turn the average living room into an oven. I have a small (4kw) stove and that keeps most of a 4 bed 1970’s house pretty warm, even on freezing day, burning just one small log at a time.
My first stove was a 1980 Hunter. I now realize that it was not a very good stove! It had double doors that did not fit tightly so it was not possible to control the burning rate by use of the air inlet controls, you had to use a flue damper and this had to be opened every time the doors were opened – otherwise the room filled with smoke. It was lined with stove bricks and had a second skin designed to give convected heat. This had the safety advantage of not having such a hot surface (we had young children) but meant that no useful heat was produced for about an hour! (Even with a radiant type of stove it will take 20 minutes from first lighting before you get useful heat). There was no airwash system so the glass in the doors was always black.
I also had a multifuel (wood, coal, peat, dried dung etc) boiler – basically a large water jacket with a firebox in the middle. This was connected to the central heating and the air inlet was regulated by the water temperature. The main problem was that it would blaze away when the pump was running but once the pump stopped the air inlet would shut down and starve the hot fire of air until enough air seeped in to cause a backdraft (see http://en.wikipedia.org/wiki/Backdraft) – this caused the top plate of the boiler to lift an inch into the air and emit a flash of flame with a loud ‘whooossh’, which upset the cat dreadfully. All wood burners will do something similar – though not as dramatically! There will be a ‘whoosh’ and some foul smelling smoke will puff out into the room. The boiler worked OK provided that you were there all the time to keep an eye on it.
There are two stoves in my current house – an extended 1970s dormer bungalow, as well insulated as I can manage and with many south facing windows. Externally the stoves are similar sizes and both would be described as small – about 4kw. However there are significant differences due to their construction.
One stove is an Aarrow mulifuel stove, it came with the house and is probably 30 years old but still in very good condition. It has an adjustable grate that can be closed to burn wood or opened to burn coal (wood burns best on a bed of ash, so always leave some in the stove, coal needs air to be drawn through the grate). The stove is lined with fire bricks and has a single glass door with an air inlet above which keeps the glass very clean. The stove works well but because of the grate and brick lining the firebox is small and I have to cut the wood up small and feed the stove every hour with hardwood or more frequently with softwood. The stove is in my office so I can look after it easily. The room is about 4m * 4m and I have to keep the door wide open to the rest of the house or I would cook in minutes, event with the stove on tickover. A lot of heat goes up the stairs, so on a cold day my office is about 23c, the upstairs rooms about 22c and the other downstairs rooms about 20c. The lip to the firebox is low and ash and hot embers fall out most times that I open the door, so I need at least a 35cm hearth. All wood will emit sparks (pine is worst) and some sparks will occur when the door is open. So I have holes in several fleeces and marks on the carpets. Natural fibres are less likely to burn, man made fibres melt as soon as a spark lands. A spark once shot across the room and it was some time before I found it smouldering behind a chair! The ashpan under the grate is no use when burning wood. The stove is connected to a metal flue that goes through a cupboard in the bedroom above and out through the roof. It is a cheap Spanish make and is OK but I’m surprised how hot the outside gets.
The other stove is Yeoman Exmoor. This a fairly cheap stove that only burns wood and is unlined, so the firebox and door are much bigger – it takes bigger logs and can be loaded with 3 times the wood that the Aarrow will take – hardwood embers will still be glowing in the morning. The design is good, the door is airtight and the three air controls all work well. It has air inlets at the base of the fire bed that make it easy to get a fire going – less effort than puffing! Much less ash falls out. Once the fire is lit the air controls have to be adjusted so that the fire is burning brightly but not too vigorously – otherwise things get very hot! The air adjustment is quite delicate and has to be adjusted as the chimney (brick with clay pot liner) warms up. The adjustment will be effected by wind and temperature outside. I have to use the poker point from time to time to stop the tertiary air inlets from getting blocked.
Because this stove has no brick lining it emits a lot of radiant heat – anything within 2m gets very hot. The rendering behind and beside the stove is cracked. Both my stoves are next to internal brick walls, these heat up and transmit heat to the next room – they can stay warm for a day after the stove has gone out. A lot of modern houses have stud partition walls – these would need protection from the heat.
Some ash gets out when you open the stove door and some gets into the air when you clean out the stove. Some dirt drops of the wood that I bring in to burn. Spiders and hibernating wasps make their homes in the wood and these escape into the house. After cutting and chopping wood I am covered in sawdust! Owning a wood burner leads to more housework!
Wood smoke does smell – your neighbours may or may not find it pleasant! The picture shows the 2 flues on my house and our neighbour’s chimney. There are no houses opposite or behind us. We smell his woodburner when in our garden and I’m sure that he smells ours – depending on wind direction.
Wood is best felled in the winter when there is little sap and then needs to dry out for the summer before it is dry enough to burn. It is best to split the wood before it dries out – this also helps it dry better. The picture shows a heap of oak that I rescued recently – this should last us most of next winter (I run a business from home so have to use some oil in the morning to get the office warm enough for the staff – or I could get up very early and light the stove). We light a fire every day and use about 6 dustbins of kindling – mainly twigs pruned from trees in the garden. This all takes a lot of storage space!
Don’t try and split wood with a felling axe – you need a wedge shaped axe like in the picture, this one has a step in the blade to stop it sticking and is asymmetrical so that it twists in the wood. Or you can buy wood ready split and dried – make sure it has been cut small enough for your stove. Ash from the fire can be spread thinly around the garden as a nutrient but too much makes the soil ‘sticky’.
Owning a wood burner is a lot more work than having a gas boiler in a cupboard. If you enjoy the process of collecting and preparing your own fuel and you are methodical enough to make sure that the stove is burning properly then you will enjoy the process. If you find it all a chore then it could be an expensive/dangerous white elephant. I suggest that before buying a stove you visit a friend who owns one and spend an afternoon splitting and stacking wood, cleaning out the ash, lighting the fire and tending to it.
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