A building’s design and the quality of it’s construction will have a major effect on the amount of air leakage. Other factors include wind against the side of the dwelling and the buoyancy effect (warm air rises pulling air in through gaps in the floor and walls).

Cold outside air maybe drawn into the home through gaps in the envelope (infiltration), resulting in cold draughts and leaving condensation.

Warm air leaking out through gaps in the dwellings envelope (exfiltration) is a major cause of heat loss and, consequently, wasted energy.

To avoid air leakage in new dwellings it is necessary to know where leaks might occur.