Many of our Customers are surprised to learn how very technical and highly regulated the residential building industry has become. Much of the increase in the cost of building homes is attributable to new regulations and codes.
Of course these regulations are designed to protect consumers, and ensure that homes are well built and energy efficient. But the fallout is often higher build costs.
The building code update issued in July 2014 required a maximum of 3 Air Changes per Hour (ACH) in any newly built home. The prior building code allowed about 7 ACH, so the new code meant that homes were required to be twice as “tight”, allowing less air in and out of the home.
How does one measure ACH? A Blower Door Test.
Professional energy auditors use blower door tests to help determine a home's airtightness. These are some reasons for establishing the proper building tightness:
*Reducing energy consumption due to air leakage
*Avoiding moisture condensation problems
*Avoiding uncomfortable drafts caused by cold air leaking in from the outdoors
*Determining how much mechanical ventilation might be needed to provide acceptable indoor air quality.
A blower door is a powerful fan that mounts into the frame of an exterior door. The fan pulls air out of the house, lowering the air pressure inside. The higher outside air pressure then flows in through all unsealed cracks and openings. The auditors may use a smoke pencil to detect air leaks. These tests determine the air infiltration rate of a building.
Blower Door Tests are now a regular part of the home building process. Here’s a look at the how this test is actually performed: