How air leakage occurs. Unintentional holes or openings in a building envelope (walls, roof, windows, etc.), coupled with pressure differences between the inside and outside at that site, cause air movement from outside to inside (infiltration) or inside to outside (exfiltration).
The two reasons for that choice are that (i) air leakage happens at the surface, not in the volume, and (ii) its the best unit, in my opinion, to express what a Blower Door is really good at measuring the amount of air moving across the building envelope at elevated pressure.
Differential pressure measurements are commonly made in commercial buildings for a number of applications, including static pressure measurements for variable-speed supply fan control, air balancing in hospitals, and for envelope and duct air leakage testing.
Finding and repairing leaks through the building envelope can improve the energy efficiency, comfort, air-quality, and moisture durability of the building stock. Typical methods of locating air leakage, such as infrared imaging or smoke tracing...
Employing air barriers to prevent air leakage and energy loss as a key piece of the building envelope has become standard practice in the construction industry.
Air leaks in buildings waste energy and can cause moisture and indoor air quality problems. Current methods for tightening building shells have relied primarily on manual sealing methods that are labor intensive and often insufficient.
3.png/400px-Control_function(good)3.png "Control (building envelope) - Energy Education")
