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Friday, January 01 2021
The Blower Door Test - IECC Energy Code Maryland

IECC Energy Code Testing - Blower Door Test

This beautiful new construction house that was completed in summer 2020 located in New Windsor, MD went through one of it's final steps to pass the energy code in the state of Maryland. IECC Blower Door Test New Windsor Maryland

The blower door test, or air leakage test was performed in accordance with the International Energy Conservation Code (IECC). 

The air leakage code requires that a house test at equal to or less than three air changes per hour (3ACH). 

The test was conducted using the ASTM E1827 - single point method. 

The blower door test was conducted five times and each measurement was recorded and entered into the report. 

Each test result yielded an ACH number less than two so the house passed with flying colors. 

In Carroll County Maryland and many other counties across the country, it is important to consider the building envelope during each construction phase so that your house is sealed properly and it can also easily pass the test. 

Tighter houses use less energy and are more comfortable.  In a tighter house you control the home's "breathing" rather than letting your energy dollars escape through the  various holes to the outside around a typical residential building's shell.










General Guide to Air Sealing a Home

The blower door test will reveal whether these measures were properly taken during the construction of the home.

1. Air barrier and thermal barrier. 

  • A continuous air barrier/pressure boundary must be installed in the building envelope.
  • Exterior thermal envelope contains a continuous air barrier.
  • Breaks or seams/joints in the air barrier must be sealed.
  • Air-permeable insulation (fiberglass batts) should not be used as sealing material.

2. Ceiling/attic

  • The air barrier/pressure boundary in any dropped ceiling/bulkhead/soffit should be aligned
  • with the insulation and any gaps need to be sealed.
  • Access opening, drop down stairs or knee wall doors to unconditioned space should be sealed.

3. Walls

  • Corners and headers should be insulated and the junction of the foundation and sill plate must be sealed.
  • The junction at the top plate and top of exterior walls should be sealed.
  • Wall insulation should be in continuous alignment/contact with the air barrier
  • Kneewalls should be sealed.

4. Windows, skylight and doors

  • The space between window and door jambs and framing as well as skylights and framing should be properly sealed.

5. Rim Joists

  • Rim joists should be air sealed (air barrier) and insulated.
  • Floors (above garage/cantilever)

6. Insulation must be installed and affixed to the underside of the subfloor plywood.

  • The air barrier must be installed at any exposed edge of the insulation.

7. Crawl Space Walls

  • Encapsulation is recommended including installing vapor barrier at the floor, sealing and insulating the walls and disconnecting the space from the outside.

8. Shafts, penetrations

  • Utility penetrations,
  • Shafts for ducts
  • Conduits for wiring
  • Flue chases that open to the outside or unconditioned space should be sealed.

9. Narrow Cavities

  • The proper insulation solution should be used to block and seal any irregular voids.

10. Garage Separation

  • Air sealing should be done between the garage and conditioned spaces.

11. Recessed Lighting

  • Recessed light fixtures installed in the thermal/pressure boundary should be air tight, IC rated and sealed to the drywall.

12. Plumbing and wiring

  • Batt insulation should be cut neatly to conform to any wiring and plumbing located in exterior walls.

13. Shower/tub on exterior wall

  • Outside walls connected to showers and tubs shall be insulated and the air barrier installed separating them from the shower and tub.

14. Electrical/phone box on exterior walls

  • The air barrier must be installed behind electrical and communication panels/boxes or air sealed boxes should be installed.

15. HVAC duct measures

16. Fireplace

  • An air barrier should be installed on fireplace walls and the doors on a fireplace should be gasketed.

Watch the Blower Door Get Set up in 2.5 Minutes




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