When they are operated correctly, wood-burning stoves are a very safe way to heat your home. But given that operating a stove involves burning wood or solid fuel, they are not without risk. Perhaps the greatest of those risks is a chimney fire, which could put your family and property in jeopardy.
What causes chimney fires?
Wood-burning stove chimney fires are usually started when a flame, spark or ember from the stove ignites a creosote deposit in the chimney. Creosote is created when flue gases cool, condense and settle in the chimney before they have managed to exit the flue as intended.
The good news is that it is easy to take precautions that will minimise the risk of a chimney fire. Here’s how to prevent chimney fires from your wood-burning stove.
Only burn well seasoned wood
You can dramatically reduce the risk of chimney fires by burning only well seasoned wood on your stove. Logs that have been chopped and allowed to air for at least 12 months will have a much lower moisture content, which will reduce the amount of creosote that builds up in your chimney. Use a moisture meter to check the moisture content of logs you’re burning. You should be aiming for less than 20% moisture.
Get your chimney swept regularly
Another key factor in preventing chimney fires is getting your chimney swept regularly by a professional chimney sweep. Your chimney should be swept at least once a year – before you start using your stove regularly at the start of the burning season. If you burn mainly logs and use your stove daily, it is also worth considering a mid-season sweep. You can use the search function on the National Association of Chimney Sweeps’ website to find a suitably sweep near you.
Operate your stove efficiently
The best way to operate your stove to avoid creosote build-ups is by having large fires. Small or smouldering fires that generate smoke result in an inefficient burn, and therefore may cause gases to condense in the flue. As a rule of thumb, you shouldn’t really see smoke coming out of the top of your chimney if the stove is burning efficiently.
Do not overfire your stove
At the opposite end of the scale to the smokey smouldering mentioned above is overfiring. This is causing your stove to operate too hot by adding too much fuel or allowing too much oxygen in by leaving the vents open too wide. When the flames are roaring above the viewing pane and up the flue, this creates conditions in which heat is lost up the chimney and could ignite a chimney fire.
Connect your stove to a twin wall flue or flue liner
It is preferable to have a narrow flue to quickly draw flue gases up and out. Connecting a stove to a wider chimney might reduce the draw and give the gases more opportunity to cool and condense inside the chimney.