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  • Benefits of Air Sealing: More Comfort, Lower Energy Bills

    It is common to hear people say, “it’s hot enough outside that I had to turn on my air conditioner.”  But it’s not because it is hot outside that you have to turn on your air conditioner, It’s because it is hot inside. Think of a drink cooler filled with ice on a hot day:  hot outside, cool inside.  Now drill a bunch of holes in the drink cooler.  Suddenly it is hot inside!  Older homes can have air leaks through the walls and roof equivalent to a two foot by two foot hole in the wall.  That’s a lot of hot air to cool down.

    “The United States Department of Energy (DOE) has concluded
    that up to 40% of the energy consumed to heat or cool a building
    is due to air leakage into and out of buildings.”  Setting Airtightness Standards

    Through scientifically studying homes, we have learned how to build better walls and roofs called a tight envelope.  Just like the drink cooler.  By testing the house using a blower door we ensure that the home is built to current building code standards.  The result is that most of the holes have been eliminated and the remaining holes are the equivalent of a 5 inch by 5 inch hole in the wall.  To make sure there is the right amount of fresh air in the house either a small four inch or six inch diameter duct brings in fresh air every time the air conditioner runs or a bath fan runs on low power drawing air into the house. 

    All this results in less work for the air conditioner and saves the home owner money through lower energy bills.  In addition the home is more comfortable.  Without all the leaks in a typical house, the cumulative effect of which equates to a hole of approximately four square feet, there are less drafts, less hot rooms and even less dust!

    For more information see:

    Residential Energy Savings from Air Tightness and Ventilation Excellence, Lawrence Berkeley National Laboratory

    Building America Solution Center Guides, such as: Continuous Air Barrier in Exterior Walls

    Building Code Requirements:

    IRC Table N1102.4.1.1 Air Barrier and Insulation Installation:   A continuous air barrier shall be installed in the building envelope:

    • Exterior thermal envelope contains a continuous air barrier.
    • Breaks or joints in the air barrier shall be sealed.
    • Air-permeable insulation shall not be used as a sealing material.

    IRC M1601.4.1 Joints, seams and connections.
    All longitudal and transverse joints, seams and connections in metallic and nonmetallic ducts shall be constructed as specified in SMACNA HVAC Duct Construction Standards—Metal and Flexible and NAIMA Fibrous Glass Duct Construction Standards. All joints, longitudinal and transverse seams, and connections in ductwork shall be securely fastened and sealed with welds, gaskets, mastics (adhesives), mastic-plus-embedded-fabric systems or tapes.

    See Residential Energy Testing  for code requirements for testing.

    Click here to view the International Residential Building Code on-line