Air Pressure Testing (also known as – Air Leakage, Air Permeability or Air Tightness) is the testing methodology used to determine the resistance of the building envelope to inward or outward air leakage, which occurs through gaps, cracks and holes in the fabric of the building.

Achieving a good level of air tightness is vital for achieving optimum levels of energy efficiency – the more cracks and gaps – the draughtier the building – which can lead to increased energy costs.