Whenever you see blue smoke billowing out of your neighbor’s chimney, it’s hard to imagine how it could possibly be environmentally sustainable to heat your home using a wood stove. The thing is, not all wood stoves are equal, and it’s important to educate yourself about the merits of heating your home with wood.
One of the most important parts of woodburning is the wood itself, using dry and well-aged wood (at least 12 months old) is critical not only for efficiency, but also for safety. New wood naturally has more water, making it more difficult to burn, and leading to more creosote buildup in the chimney. Creosote is browny-black buildup that occurs mainly when fires are either smouldering, or when improperly aged wood is burned. Creosote can subsequently build up in chimneys and in some circumstances can catch on fire, creating dangerous chimney fires.
Another critical component of woodburning is having a good stove. There are a lot of misconceptions about woodburning, particularly around the efficiency and emissions of woodstoves. Older woodstoves (particularly stoves over 10 years old) are basically burn-boxes with a pipe that attaches to a chimney. They are inefficient and lead to more creosote buildup largely because they are more difficult to get burning and are unable to burn smoke and ash.
Efficient wood stoves have the ability to burn smoke and ash, making them up to 80% more efficient than traditional stoves, and emitting a fraction of the amount of particulate matter that older stoves do. As efficient stoves burn, gas and ash is caught in metal flutes that line the top of the burn box. Those flutes direct the gas and ash back down towards the fire, creating a sort of rip-curl effect that makes flames swirl and dive. Gas and ash is burned off, meaning more heat is generated and far less particulate matter makes its way out of the stove pipe. When a high-efficiency wood stove is being burned properly, it’s usually impossible to see the smoke coming out of the stove pipe! Some stoves even have a catalytic converter (just like cars), and are virtually emission free.
A critical element to the proper function of a high efficiency stove is to burn at an appropriately hot temperature. Not burning hot enough drastically reduces the efficiency of the stove and creates creosote buildup. Burning too hot can overheat the appliance and creates safety hazard. Burning in the “burn zone” is safe and efficient – and the only way you can really know if you’re in the burn zone is by using a wood stove thermometer (which can be purchased at virtually any hardware store) and monitoring the temperature.
Please note, it’s also very important to have a certified Wood Energy Transfer Technologist (WETT) install any wood stoves, and to ensure that your home is properly insured to have a wood stove present.