Exactly how much air is drawn out of your chimney depends on the ‘stack effect’, which relates to the movement of air into and out of buildings. It’s influenced by various factors, like the height of your house and the difference in temperature between inside and outside.
Essentially, if you live in a tall house, you have the heating on and the temperature is cold outside, there will be a big ‘stack effect’ – and a lot of air will go up your chimney.
As this warm air rises, it needs to be replaced. So cold air is pulled in, usually from around doors and windows, creating the chilly draught that you can feel (and hear when it’s windy).
By cutting out draughts, you can keep your home nice and cosy. You will also use less heating, which is a win win: reducing your bills and helping the planet. The climate is changing due to emissions of greenhouse gases resulting from human activity, and heating buildings currently accounts for more than a third of the UK’s emissions.
Skyscrapers deal with the ‘stack effect’ by having revolving doors instead of normal ones, to create a ‘seal’ on the building. But what can you do to draught-proof your chimney? You have a couple of options…