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Blower Door Test

Blower Door


What is a Blower Door Test?

A blower door test is a tool used in new and existing homes to find the energy efficiency of the home. By putting a negative pressure on the home, we are able to locate all air leakage coming inside the air-conditioned space, thereby repairing it as needed and retesting the home to see the air tightness increase on the house.

What is a passing score?

A passing score in the State of Florida is an infiltration rate below 7 air changes per hour. In other states such as Illinois, the infiltration rate is to be no more than 5 air changes per hr. However, most of the country requires homes to be below 7 ACH50.

Note: In the State of Florida, an infiltration rate below 3 air changes per hour, requires outside mechanical air ventilation. Homes using Icynene Insulation (Spray Foam Insulation) typically have a score of 2 ACH50(air changes per hr.).  Outside air ventilation is required to prevent carbon dioxide and other harmful gases from building up in a home or structure, or otherwise termed as "sick house syndrome".

After recently being added to the International Energy Conservation Code in 2015, it is required by most county and city building codes on all new construction homes and new additions. The test works by using a fan to pull air out of the house, lowering the air pressure inside. Then, the higher outside air pressure flows in through all unsealed cracks and openings. A certified energy auditor is able to pinpoint where any leaks are.

How it Works

A blower door test works by creating vast pressure differentials between the interior and exterior of a home. Proper testing pressure for a structure, as identified in the International Energy Conservation Council, is 50 pascals. By creating a negative 50 pascals pressure within a home, the outside pressures attempt to equalize the pressure difference thereby exposing leaks, gaps, and penetrations within the drywall envelope of the home or building, which is then measured out and determines if a structure is passing or not. 

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What is a Certificate of Occupancy?

A Certificate of Occupancy is an issued document stating a building or residence is in compliance with local building codes and zoning departments. This document grants a structure as habitable. In the state of Florida, all new construction and major renovations requires a blower door test in order to receive a C/O. 

Frequently Asked Questions
  • Do I need a blower door test?
    If you have just about finished a residential home, or you have done major renovations, then YES, you will need a test(s) done, just before your get your final building inspection in order to receive your Certificate of Occupancy. These tests are also a great additional inspection for real estate, prior to purchasing a home or commercial building.
  • Where can I find what tests need to be done?
    Typically on the energy calculations sheet in fine print near the energy auditors seal.
  • At what point of new construction is a blower door test performed?
    A blower door test can be performed at any time, but for Florida Code compliance, it-is conducted just before the Certificate of Occupancy (CO) is issued, after all piping, wiring and other penetrations of the building thermal envelope have been sealed. Please make sure to have all drywall openings closed up before calling us out for an inspection. If Icynene (Spray Foam) Insulation has been used a blower door test can be performed earlier on in the build. If regular blown-in or batt insulation has been used it is recommended that all electrical covers, drywall holes, and all penetrations otherwise, be finished. If baseboard is noticeably above the floor throughout the house, it is also recommended that they be caulked to the floor to insure a passing score.
  • Can we be inside while the test is performed?
    Workers and homeowners may be in the house during the test, we will just need all the doors and windows closed. Results are given on the spot after performing the test, which takes about 30 minutes. The house will only need to be closed up for a very short duration after the blower door setup is installed in an exterior door.
States that Require a Blower Door Test





South Carolina

North Carolina





New Jersey

New York



New Hampshire




















New Jersey


Rhode Island






District of Columbia

City of Phoenix,Arizona

City of Little Rock, Arkansas

In Colorado: Larimer County, Fort Collins (Multi-Point Test), Loveland, Boulder County, City of Boulder, Denver (city/county), Castle Rock, Aurora, Broomfield city/county, Commerce City, Federal Heights, Thornton, Lafayette, Longmont, Louisville, Superior, Golden, Littleton, Wheat Ridge, Evans, Greeley, Frederick, Colorado Springs

Kansas: Lawrence County, Kansas City

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