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Florida’s Blower Door Test Overview by RunBrook

Florida’s Blower Door Test: 3 Things Multifamily & Production Home Builders Need to Know

By Matt Zirkelbach


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Starting on July 1, 2017, blower door tests became a requirement in Florida’s building code for all new residential homes and multifamily buildings three stories or less. This means that blower door tests are now more important than ever for multifamily and production home builders. To help you navigate through this new development, below are the three key things to know about blower door tests in Florida.

What’s a Blower Door Test? A blower door test determines: 1) The overall airtightness of a home by revealing the air infiltration rate and 2) Where any air leaks might be hiding. Proper home airtightness is important because it reduces energy consumption, avoids moisture condensation problems, prevents air leaks and helps identify how much ventilation is needed to provide acceptable indoor air quality (IAQ).

How Does the Test Work?

Blower door test equipment includes a frame and flexible panel that fit inside an exterior doorway, as well as a variable-speed fan and tools for measuring airflow and air pressure. During a blower door test, the fan is used to pull air out of the house, thus lowering inside air pressure and causing higher-pressure outside air to flow in. This enables technicians to measure air leakage and identify sealing vulnerabilities.

3 Things to Know about Florida’s Blower Door Test

1) Comply with Code

A supplement to the fifth edition of the 2014 Florida Building Code made several updates to Energy Conservation Code Section R402.4.1.2 regarding blower door tests. These include:

• July 1, 2017 was selected as the start date for mandatory building air leakage testing, thus making blower door tests a code requirement for all new residential homes and multifamily buildings three stories or less.

• A home must have seven air changes per hour (7 ACH50) or less in climate zones one and two (all of Florida) in order to pass the blower door test. This means that if a home has wind blowing against it at 20 miles per hour (the equivalent of 50 Pascals pressure), the total volume of air within the house would exchange with outside air up to seven times. All homes are tested at 50 Pascals pressure difference to maintain consistency.

2) Build Tight, Ventilate Right

In addition to being required by Florida building code, the blower door test ensures that contractors seal the home properly so you can build tight and ventilate right. For example, you can answer these key questions: Did your window installer do a good job? Was weather stripping done as expected? Were gaps or cracks left that can lead to problems with mold, IAQ and energy efficiency?

Blower door test results also allow you to document the airtightness levels needed to qualify for green building and energy efficiency programs for homes and multifamily construction, such as Leadership in Energy and Environmental Design (LEED), National Green Building Standard™ (NGBS) Multifamily, Green Globes, ENERGY STAR and Florida Green Building Coalition (FGBC).

3) One Step Closer to a HERS Rating

The Home Energy Rating System (HERS) Index is the industry standard for measuring a home’s energy efficiency, as well as a nationally recognized system for inspecting, testing and calculating a home’s energy performance. A HERS rating consists of a blower door test, a duct leakage test, building energy modeling and a thermal bypass inspection (pre-drywall), and the lower the score the greater the energy efficiency.

There are many benefits to receiving a positive HERS rating. For example, HERS ratings are required for many green building programs, as well as to be eligible for incentives, such as the 45L tax credit, which is worth up to $2,000 per home.

4) BONUS: The Test is Easy to Do A certified professional must conduct Florida’s blower door tests, which are easy to do. As a certified rater, RunBrook’s energy rating team has done thousands of tests, and we’re especially equipped for multifamily and production home projects with hundreds of residences. We make sure that blower door tests are performed with skill, in a timely manner and in close coordination with the construction manager.

For more information, contact RunBrook: