BASC Search | Building America Solution Center

Seams and connections in rigid metal ducts are air sealed using tape or mastic.

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Caulk was used here to air seal the gap between the electrical box and the drywall.

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Unvented air-sealed crawlspace is insulated along the perimeter walls with rigid foam

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Wrong - The air barrier is not sealed (picture taken from garage looking into house).

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Right – Air barrier and penetrations sealed between porch attic and conditioned space

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Air seal door and window rough openings with backer rod, caulk, or nonexpanding foam

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Pumpkin Ridge Passive House Video #15: Window Install Prep & Air Sealing

Video

Video describing how to prep and air seal the wall cavity for window installation.

Building America Energy Performance Brief: Air Sealing Duct Boots and Duct Chases

Case Study

Case study describing how to inspect and air seal around duct boots and chases in order to limit air leakage in a home.

Wrong - Rigid insulation blocking is installed but not air-sealed with spray foam around edges.

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Right - Walls and ceilings shared by the garage and living space must be air sealed and insulated.

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Plan view showing air sealing between exterior walls and intersecting interior walls

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A fire-rated sealant "putty pad" is used to air seal an electrical outlet box

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Two pillows and two garbage bags are used to make a chimney air sealing pillow

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Right - Ducts and heat pump cabinet are properly sealed with mastic, high MERV filter is installed, and duct and refrigerant lines are air sealed at ceiling.

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Spray foam insulates and air-seals the ceiling deck and top plates of this vented attic.

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The trim-to-flooring seam can be caulked to provide an air seal at the base of the walls.

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Air seal all holes and seams in the furnace cabinet with mastic, foil tape, or putty

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Right – A flexible tape is used to air-seal around wiring holes in the coated sheathing.

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Right – All of the cabinet seams in this HVAC air furnace are sealed with an approved metal tape.

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Right - Mastic is being installed to air seal the wood-to-wood joints in this wall.

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Canned spray foam can be used to air seal the rough opening around the windows

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The baffle is air sealed in place with spray foam before installing fiberglass or cellulose insulation

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Air Sealing Retrofits: Conducting an IR Camera Inspection of an Existing Home - Return Grills

Video

Video showing how to use an infrared camera to identify and check for air leakage from the return grills of the home.

Air Sealing Retrofits: Conducting an IR Camera Inspection of an Existing Home - Recess Lighting

Video

Video showing how to use an infrared camera to check for air leakage around recessed can lights during a blower door test in winter.

Closed-cell backer rod is installed for air-sealing window and door rough openings.

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Fiberglass mesh tape is installed around a duct boot in preparation for air sealing with mastic

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Duct boot is air sealed to ceiling by covering the seam with fiberglass mesh tape and mastic

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Duct System Flammability and Air Sealing Fire Separation Assemblies in the International Residential Code

Reference

Report identifying two barriers that limit the ability of builders to explore opportunities for higher levels of energy efficiency in housing: the use of duct system materials that inherently achieve airtightness and are right-sized for low-load houses, and, the ability to air seal fire separation...

Right - An installer uses canned spray foam to air seal joints in an existing subfloor.

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Right – Chase capped with rigid air barrier and duct work penetrations properly sealed

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