Sune Nightingale on installing a wood-burning stove
There’s nothing like a real fire to make your home feel like the best place in the world to be. Apart from the obvious – and more romantic – benefits of a woodburning stove, there are increasingly other reasons to consider installing one in your house.
With environmental concerns over harmful CO2 emissions and demand for fossil fuels predicted to outstrip supply well within in our lifetime, (Shell predicts that demand will outstrip supply of easy-to-access oil and gas by 2015), there’s never been a better time to rethink how to heat your home.
Wood is an increasingly popular, and very low carbon, sustainable fuel, (though not carbon neutral as many people try to maintain), that can often be sourced locally, for free. Modern stoves are efficient, come in many sizes and styles, and some can even provide your hot water and central heating.
buying a stove
You should budget around £100-£400 for a second hand stove and £450-£1500 for a new one. Your chimney system may cost you another £600+. You must also think about installation costs if you are not self installing.
The internet is a great source of information on woodburners. You can find second hand stoves on eBay and in your local papers. Spare parts for current stoves can be found on the Net as well. When checking out a second hand stove, look out for: cracks or warping in the body, damage to the grate or baffle plate and missing or broken firebricks. (A baffle plate is a metal plate that sits inside the stove, above the fire and makes the hot flue gases travel further before they exit the stove. This increases efficiency). New stoves can be bought online, or from a local dealer.
Before you buy a stove, it’s important to check whether you live in a smoke control zone where it is illegal (and irresponsible) to burn wood for heating, unless you have an “approved stove”. A map of UK smoke control zones and a list of approved stoves can be found at uksmokecontrolareas.co.uk. Approved stoves have low particulate emission levels, which reduces air pollution. Even if you do not live in a smoke control zone, choosing an efficient stove with low emissions is a good idea: you will use less wood and it’s the more responsible thing to do for your fellow humans. The stove pictured above is a cast iron multifuel stove which Spark reader Carrie Hitchcock has installed in her home. It has a ‘cleanburn’ system using airwash, (little holes in the stove) which means it’s one of the few wood burners approved for smokeless zones.
You also need to think about insulating your chimney system. When flue gases cool, tar is deposited in your chimney and this tar can cause chimney fires. (Around 15% of fire brigade calls for fires in the home are for chimney fires!). By using an insulated chimney you keep the flue gases hot, which reduces tar deposits and reduces your risk of a chimney fire. There are several ways of insulating your chimney, one of the most common being to run a flexible metal liner down the chimney and then insulating that. For newbuild houses, a pumice chimney system is an excellent choice.
If you are a practical person, with a knowledge of building, then you should be able to install your stove and chimney system yourself. It is legal to self-install but the work comes under building control and you should make enquiries before you start (there may be local regulations you need to keep to). It’s a good idea to do a lot of research into the building regs you must keep to and how to install the stove/chimney in the best and safest way: ask for expert instruction, advice, tips, tricks, and snags to watch out for. Often people have “a mate who just connected his stove to the chimney and it works fine,” and this is probably true, but it is probably not safe. When you’ve finished the job you must arrange to have the installation inspected and signed off at the end by a building control officer (there is a charge for this).
If you call in an expert to install your stove then check that he or she is HETAS registered. (HETAS is the official body recognised by government to approve solid fuel domestic heating appliances, fuels and services). A registered installer can charge between £300-£1000+ depending on the job.
Freshly felled wood contains 30-60% water, seasoned wood must be dried to 20% or less. Wood should be felled in winter, cut, chopped and then dried for at least the summer season (hence the word “seasoned”) although two seasons is better.
Some suppliers may try to sell you unseasoned (30%+ moisture) wood, claiming it is seasoned. Not only are you being ripped off, it is also dangerous, increases the risk of chimney fire, increases particulate emissions, is bad for your stove and chimney, plus the fire will not burn well or give a decent heat. The end of a seasoned log tends to have cracks in it (because the wood shrinks as it dries).
Ash makes good firewood as it already has a low moisture content when it is felled. Softwoods like pine make good kindling but give less heat, weight-for-weight, than hardwoods, so you should not pay as much for them. If you collect waste/skip wood or offcuts then make sure that the wood is untreated – if it is treated then it will release noxious chemicals when you burn it.
Store your logs in a well ventilated log shed. Old pallets make good log shed walls that still let air through. This picture is of a wood stack that I made in Denmark (home of the wood stove) to season some freshly cut logs. This square stack has four upright branches, sharpened and driven into the ground at each corner, and then tied together diagonally at the top to stop the stack widening.
heating/hot water systems
Stoves can come with boilers to provide hot water. This can vary from a system heating a couple of radiators to running an entire central heating and hot water system from your stove. It is also possible to link up a boiler stove to an existing system run by a gas/oil boiler to reduce your bills and CO2 emissions. You can also link in solar panels: solar thermal panels and a wood stove are perfect partners, with the stove providing hot water and heating in the cold months and the panels taking over during the warmer months.
Talk to an experienced heating engineer about the various methods and requirements for combining a stove with your heating/hot water system. One common method is to combine multiple heat sources by using a relatively large multicoil hot water tank (or accumulator/storage tank) as a central point in the system which the stove, solar, gas boiler, etc all heat up. Hot water is then piped to your taps and your heating also comes from this tank.
this article was published in Spark issue 55 - Winter 08/09
all details correct at time of ging to press - please make your own checks
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