Blower door test is an air leakage test of a building. It involves the controlled injection or extraction of air from a building to create positive or negative pressure. In this way, it is possible to detect leaks in the building envelope.
During the test, it is measured how much air passes through leaks in the building envelope - walls, roof, windows or construction joints. The result of the test is expressed by the coefficient n₅₀, which indicates the number of air changes per hour with a pressure difference of 50 Pa.
This test is particularly important in timber-framed and energy-efficient houses, where airtightness is very important for the reducing heat loss and ensure proper operation of mechanical ventilation with heat recovery - recuperation. Blower door testing is also required in some subsidy programmes and passive and low-energy building standards.
