Several factors contribute to poor indoor air quality that can be easily controlled. Air pressurization greatly affects the indoor air quality of a home or building.
Air flow is created by pressure differentials. Air flow always flows from higher relative pressure to lower relative pressure. If more air is supplied to a room than exhausted, the excess air leaks out of the space and the room is said to be under Positive Pressure. If less air is supplied than exhausted, air is pulled into the space and the room is said to be under Negative Pressure.
If a home or building has too much positive air pressure, it will allow for conditioned air to escape the home causing costly energy concerns.
Negatively pressurized homes allow for unconditioned and unfiltered air to be drawn within the home or building. Debris will enter through cracks and crevices, opened doors, windows, etc…
What’s the Ideal Air Pressurization?
It is ideal to achieve neutral to slightly positive air pressurization. Though there is a slight loss of conditioned air, a slightly positive pressured home will provide comfort and prevent outdoor contaminants from entering the home or building.
ASHRAE Standard 62.1 “Ventilation for Acceptable Indoor Air Quality” requires proper ventilation and a slightly positive pressurization of buildings. Maintaining a small positive air pressure, relative to the outdoors, limits the entrance of outdoor moisture and is a very common strategy to prevent mold and mildew formation in a building.
How Can You Monitor or Control Air Pressurization?
Air pressure can be monitored through an energy auditor. An energy auditor will use of a blower door & smoke test to determine the location of air leaks. After the test is performed steps can be made to improve air pressurization.