Faqs

The easiest and most common way to identify air leakage paths is to feel them during or after the test. By depressurising the building/unit (i.e. drawing air out using the fan(s)), the air paths [...]

For houses and flats of standard construction, it is possible to achieve reasonable air tightness without having to use specialist products and techniques but it requires close control of trades [...]

Timing is key, the majority of test failures occur because the building/unit simply isn’t sufficiently complete. However, leaving it to the last minute puts added pressure on the test if there is [...]

The test is a pressure test whereby fans are used to create a pressure difference between the inside and outside of the building/unit. By knowing how much air is being used to maintain this [...]

The maximum air permeability allowed on any tested unit is ‘10’ but because of the trade-off of factors to achieve the overall calculated energy performance of the building/unit it is more [...]

All new buildings of all types.  It is possible to avoid testing individual houses and small commercial buildings but it means using a very poor, assumed air permeability value in energy [...]