Blower Door Test
Air tightness and air changes are measured by the Blower Door Test. For health, energy efficiency and passive house principles these are important metrics.
A Blower Door Test is used to measure the air tightness or air changes per hour in your dwelling. It works to prove the enclosed interior of your living space, is major benchmark for passive house certification and a simple way of determining leaks and possible energy loss in your space.
After calculating the entire volume of the space, all windows and opening doors are sealed, a fan blower is then mounted to the front door of the space. The ‘Blower Door’ itself is often a fan on an airtight membrane with a pressure sensor on either side. The Blower Door then pressurises and/or depressurises the air envelope of the space, recording the difference in pressure from inside and outside, as net airflow between or air changes per hour (for passive house certification a dwelling must not exceed 0.6 air changes per hour).
Air tightness is a corner stone of passive house design principles and energy efficient building. The reason is if you can create a perfect border — or contained environment — you can work with the inputs and outputs of a system much more easily. You can calculate and capture the energy coming in and going out of your home energy system. Air leakage can be up to 40% of heat load in a dwelling. For saving energy and ultimately money the Blower Door Test is crucial. From a health perspective air tightness is also important, fresh air should be coming in via openable windows or ventilation systems, not via leaks and gaps in wall or roof cavities.