The equipment
An adjustable frame and fabric panel seal into an exterior doorway. A calibrated fan sits in the panel, and a gauge measures the pressure difference across the building shell along with the airflow moving through the fan.
How the test is run
The fan pulls air out of the house until the pressure inside drops to 50 pascals below the pressure outside. The amount of air the fan has to move to hold that pressure is the leakage rate.
Reading the result
The leakage rate is expressed as air changes per hour at 50 pascals, written ACH50: how many times the air inside the house would be replaced with outside air in an hour if the house stayed at that pressure. A lower number means a tighter building shell.
The limit in this area
Florida sets the limit for new homes under the Florida Building Code, Energy Conservation. In Climate Zone 2, which covers the counties we serve, that limit is 7 ACH50.
Blower door test questions
Does the house have to be empty for the test?
Is the attic part of the test?
Is an attached garage part of the test?
Sources
- 2023 Florida Building Code, Energy Conservation, Eighth Edition, Chapter 4 [RE], R402.4 Air leakage (Mandatory), R402.4.1.2 Testing: https://codes.iccsafe.org/content/FLEC2023P1/chapter-4-re-residential-energy-efficiency
- 2023 Florida Building Code, Energy Conservation, Chapter 3 [RE], Table R301.1 Climate zones by county: https://codes.iccsafe.org/content/FLEC2023P1/chapter-3-re-general-requirements
- 2023 Florida Building Code, Energy Conservation, Eighth Edition, edition and effective date: https://codes.iccsafe.org/content/FLEC2023P1