Chimneys & Flues

All chimneys and flues should be regular shaped, as straight as possible with sides as smooth as possible. All of these factors help to ensure that the gases from the fire are efficiently removed and that a fresh supply of clean air is drawn into the stove. The faster the gases move in the flue the less it leaves on the walls of the flue. Soot and creosote build up in the flue can seriously affect the effectiveness of the flue and consequently the efficiency of the stove. Insufficient ventilation can result in carbon monoxide being released into the house, CO being potentially fatal at concentations of only 400 parts per million.

Unlike the chimney of an open fire a stoves' flue is largely sealed from the room and doesn't allow draughts into the house. The flue should retain a high level of heat, hot gases move faster. Liners are available, which protect the brickwork of traditional chimneys, provide a smooth sided flue and also reduce the available space. This reduction is not bad, by compressing the gases in passage you speed them up and encourage condensation.

Flue liners are important for older chimneys which may have thins walls, especially in thatched houses. Stoves will produce hotter flue gases so thin chimney wall will not protect the surrounding parts of a building from that heat. A flue liner will insulate against these hotter gases.

Your chimney will need maintenance, cleaning at least once a year for solid fuel, once a season for wood. Sweeping the chimney ensures that the flue remains unblocked and free from build ups of soot, tar or creosote. Even partially blocked flues can reduce the efficiency of your stove and can result in carbon monoxide poisoning. The best time for having your chimney swept is at the end of the winter when you won't be using it for a while. Unless, of course, your chimney is not fitted with a bird guard, in which case it is best to wait until the end of the nesting season so that any nests are removed. If you are considering sweeping your own chimney t is sometimes a requirement of insurance policies that any 'in use' chimneys are swept by a professional sweep. Of course a professional sweep will also have all of the right equipment and won't leave a mess.