Blower Door Guidance

New Construction

Overview for Blower door for New Construction

The blower door test is required by energy code for all residential buildings and all R-2 occupied buildings following the 2021 and newer IECC . The purpose of the test is to measure the air that infiltrates a residential unit or home from unplanned sources. These sources are innumerable, but include attic air moving past HVAC and electrical fixtures, outside air following plumbing lines

Air Sealing during the Rough Stage

While the blower door test is performed at final, preparation for the test starts during the rough stage of construction. Holes in the building envelope are more easily identified before drywall and insulation are installed. There are some important pointers to remember when planning for a blower door test.

  1. No light should be visible through the building envelope.

  2. Insulation does not prevent air leakage by itself.

  3. Inspect the work of your polyseal installer.

Blower door sealing is more difficult for smaller units. Smaller units have the same number of penetrations through the building envelope as a larger unit/dwelling, but have a reduced leakage allowance due to the reduced floor area which is how the target is calculated.

Air sealing during the final stage

NOTE: All sealing guidance recommends sealing the rough install box to the drywall or finish surface prior to installed trim plates or grilles.

The following items should be addressed and sealed for ALL projects:

  1. Weather-stripping installed on all exterior doors

  2. Penetrations through drywall at HVAC supplies and returns.

  3. Penetrations through drywall at exhaust fan housing

  4. Penetrations through drywall at all wet-box locations (refrigerator & washers)

  5. Penetrations through drywall at ceiling electrical boxes. Rough box should be caulked to drywall.

  6. All penetrations into the mechanical /HVAC closet

Other Common issues:

  1. Mechanical exhaust damper(s) stuck open. Check for Bathroom exhaust, fresh air intake, and dryer vent.

1. Caulk Base Boards

This will be where I explain breifly what is going on or why caulking this is a good idea. Check your bookmarks.

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