In July 2017, the Florida Building Code was updated to require new residential homes to undergo a blower door test—and pass it. In Section 402.4.1.2, the blower test must have 7 air changes or fewer an hour. The Florida Building Code also specifies that “blower door testing shall occur after the rough in and after installation of penetrations of the building envelope, including penetrations for utilities, plumbing, electrical, ventilation and combustion appliances.”

With a blower door test, we’re mainly concerned with air leakage, especially in new construction homes and older homes where air leakage can be common. For certain, airflow is a safety issue.  You can only imagine that during a hurricane, your potential homeowner would be concerned with how much air pressure is being exerted through various cracks and doorways throughout the house. 

That’s what the inspectors at Acusystem Inspections are here for: We have the knowledge, the equipment to measure, and the experience necessary to pinpoint areas of the house that need to be addressed. Blower Door Testing is a vital step in the construction process to test the structural balance of your home or commercial build and to recommend correcting any structural concerns.

We can as accurately gauge the airflow through narrow cracks and seams as we can through your open passageways. Let our experts test various critical points—especially around door frames—so you can be rest assured the leakage of air in your structure doesn’t exist at a dangerous level.

When we come to you, we’ll apply consistent and measurable pressure to the building and grant you a comparison with other homes deemed as highly safe. In Florida especially, airflow must be calculated with caution and concern; obviously, we never know when another storm will threaten our homes. By calling one of our experts at Acusystem Inspections, we can schedule a Blower Door Test that will fit your construction timetable.

A blower door is a type of fan that pulls air out from the inside of the home, causing the pressure in the home to drop. If air can re-infiltrate your home during the blower door testing, it will affect the air pressure in your home, which will be indicated on the calibrator on the blower door fan. To prepare for the blower door test, the following steps are taken:

1. All exterior doors, windows, and the fireplace will be closed (not sealed).
2. Exterior ventilation systems are closed.
3. Dampers, including the exhaust, intake, flue, and backdraft dampers are closed.
4. Interior doors are opened.
5. HVAC systems are turned off, and the ducts and supply and return registers are not sealed.

Then, the blower door is installed, and the process of removing the air and monitoring the air pressure begins.

According to the Florida Building Code, the readings during a blower door test cannot change over 7 times per hour in Climate Zones 1 and 2 or more than three times per hour in Climate Zones 3 through 8. To help ensure the home you are building passes its blower door test, here are a few things you can do or make sure are present.

• If there is a fireplace, it must have an air barrier.
• The HVAC register boots must be sealed to the drywall or subfloor if they penetrate the building envelope.
• Common walls between dwellings must have an air barrier installation.
• If your exterior wall has an electrical or phone box, you can either ensure the existing air barrier goes beyond the box or the boxes need to be air sealed.
• A shower (or tub) installed on an exterior wall must have an air barrier between the exterior wall and the fixture.
• All the wiring and plumbing in your home need to have some type of insulation.
• Any recessed lighting fixtures not installed in a conditioned space will need to be sealed to the drywall and have an IC (Insulation Contact) rating.
• Air sealing needs to be present between air-conditioned spaces and the garage.
• If the home has any narrow cavities, it must have the blown, spray, or batts insulation.
• Penetrations and shafts around an unconditioned or exterior space must be sealed.
• Crawl spaces are required to have permanent insulation and any overlapping joints need to be taped up.
• Also, if there is exposed ground around the crawl space, then it needs to have a Class 1 vapor retarder.
• Flooring must have insulation that contacts the subfloors decking and exposed edges require an air barrier.
• Rim joists need to be insulated and have an air barrier.
• The space between the frame and door jamb or frame to window must be sealed.
• The foundation junction and sill plate are required to be sealed.
• All headers and corners of a wall must have insulation.
• Knee wall doors, drop-down stairs, and attics (with exception of unvented attics) must be sealed.
• Drop ceilings and soffits need an air barrier in line with the insulation and if there are gaps, then they must be sealed.
• Air permeable insulation cannot seal but could be used inside an air barrier.
• Exterior thermal envelop insulation used for the building envelope air barrier or any of the frame walls must be aligned and in contact.

AcuSytem Inspections offers over a dozen inspections for private residences and commercial properties. Blower door testing and new construction inspections are two of the many services we provide to builders and residents of Tampa Bay and surrounding counties. Contact us today to schedule a blower door test you are building—or an older home you own or are buying—to see how airtight and energy efficient your home is.