As of July 1st, 2017, all new residential homes in Florida must pass a Blower Door test to meet energy code.
Each building must have 7 air changes per hour (7 ACH50) or less in order to successfully pass the Blower Door test.
Blower Door tests simulate the wind blowing against a building at 20 miles per hour, in which case the total volume of air within the house would be exchanged with outside air 7 times. The 20mph wind is equivalent to 50 Pascals (Pa) of pressure difference. A Blower Door Fan simulates these conditions during a test.
All buildings are tested at 50 Pa pressure difference to allow for comparisons to be made between homes/structures, no matter the size or plan type. In the State of Florida, buildings which comprise of 3 stories or less must follow the building code with respect to these tests.