What to think about when draught-proofing your home

What gaps should be left for ventilation?

If a vent has been created for a specific product such as a fire or kitchen appliance or in a room that requires additional ventilation like a bathroom then it is very important to keep these vents open. You may be able to feel a strong draught coming through them but these are bring in fresh air and oxygen which is needed to avoid carbon monoxide poisoning. The vents in the bathroom are creating air exchange to remove moist air which could cause a build-up of damp resulting in damage to the building or mould spores which are bad for your health. When looking for draughts to eliminate it is the uncontrolled ventilation of air leaking in where it shouldn’t do that you should seek out.

How can draughts be located?

It can be quite frustrating pin-pointing the source of a cold draught. Often you can feel the cold air but struggle to find exactly where it is coming from. Using a lit incense stick or candle can assist with locating some draughts. The Smoke Pencil is a gadget that emits a steady stream of smoke-like vapour which is operated by a trigger, enabling the user to release a fine plume of smoke at various angles which makes it easier to located hard-to-find draughts.

a smoke pencil with its trigger compressed and a plume of vapour that looks like smoke is emitted. The smoke is drawn to a an air leak point

What are the energy savings of a draught excluder?

With a leaky building there are so many variables that it can often be difficult to calculate the energy savings of specific draught exclusion measures. However with chimneys the airflow can be attributed to a limited range of factors so the amount of energy saved by fitting a chimney draught excluder can be calculated more readily.

The energy savings from fitting a Fireplace Heatsaver can be seen here. The savings include secondary measures, that is, the savings you get from not lighting the fire once you’ve got the chimney blocked since you’re likely to use the fire less.

Similarly, the savings using a Chimney Balloon include the savings from not using secondary heat sources.

an image of the inflated chimney balloon chimney blocker blocking the chimney

BSRIA also tested the blockage factor of the Chimney Sheep and calculated the energy, carbon, and cost savings of fitting the product. This study was done in association with OFGEM, is UKAS approved, and does not include secondary measures, so all savings made from using the Chimney Sheep® are simply those gained from blocking off the chimney. Savings from not using secondary measures would increase the total savings given in the calculations, for parity with the Fireplace Heatsaver and Chimney Balloon.

A diagram of chimney sheep blocking a chimney