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Air seal whole-house fans to minimize air leakage.

Air seal whole-house fans to minimize air leakage.

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Air Sealing Bathroom and Kitchen Exhaust Fans

Guide

Guide describing how to air-seal bathroom and kitchen exhaust fans.

Air sealing at whole house fan enclosure

Air sealing at whole house fan enclosure

CAD File

Wrong – Kitchen exhaust has not been air sealed

Wrong – Kitchen exhaust has not been air sealed

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Air seal around kitchen and bathroom exhaust fans to keep conditioned air from leaking into unconditioned space.

Air seal around kitchen and bathroom exhaust fans to keep conditioned air from leaking into unconditioned space.

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Air seal and insulate around the exhaust fan with a rigid foam box

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Wrong – Whole house fan installed with holes in surrounding platform that need to be air sealed

Wrong – Whole house fan installed with holes in surrounding platform that need to be air sealed

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Right – Fan with a cleanly cut and properly sized hole has been air sealed to drywall

Right – Fan with a cleanly cut and properly sized hole has been air sealed to drywall

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After air-sealing the exhaust fan box, re-install the fan, and lights if needed, and re-attach the cover

After air-sealing the exhaust fan box, re-install the fan, and lights if needed, and re-attach the cover

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The fan was removed from this exhaust fan box to access and air seal the seams with metal tape and the holes in the housing with canned spray foam

The fan was removed from this exhaust fan box to access and air seal the seams with metal tape and the holes in the housing with canned spray foam

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The polyethylene ceiling vapor barrier is sealed to form an air barrier around the exhaust fan in this very cold climate location (≥ CZ 6).

The polyethylene ceiling vapor barrier is sealed to form an air barrier around the exhaust fan in this very cold climate location (≥ CZ 6).

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Some whole-house fans are equipped with an automatic drop-down cover to provide an air seal at the ceiling level when the fan is not in use

Some whole-house fans are equipped with an automatic drop-down cover to provide an air seal at the ceiling level when the fan is not in use

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The jagged edges of the cutout around this ceiling exhaust fan require canned spray foam, metal tape, or fiberglass mesh tape and mastic to air seal the gaps and keep conditioned air from the home from escaping into the attic

The jagged edges of the cutout around this ceiling exhaust fan require canned spray foam, metal tape, or fiberglass mesh tape and mastic to air seal the gaps and keep conditioned air from the home from escaping into the attic

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Wrong - The IRC prohibits the use of flex duct for kitchen exhaust and only permits PVC duct for downdraft systems that meet specific exceptions; also, gaps at the ceiling have not been air sealed.

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Wrong - Bathroom fan not caulked and sealed

Wrong - Bathroom fan not caulked and sealed

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Wrong - Bathroom fan not caulked and sealed

Wrong - Bathroom fan not caulked and sealed

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Right – Kitchen exhaust penetration has been sealed with caulk

Right – Kitchen exhaust penetration has been sealed with caulk

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Wrong – Roughly cut hole that is larger than the fan, making it difficult to seal

Wrong – Roughly cut hole that is larger than the fan, making it difficult to seal

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Wrong – Roughly cut hole that is larger than the fan, making it difficult to seal

Wrong – Roughly cut hole that is larger than the fan, making it difficult to seal

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Whole house fans draw cool night-time air in through open windows and expel hot house air into the vented attic

Whole house fans draw cool night-time air in through open windows and expel hot house air into the vented attic

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This fan has noticeable gaps between the fan box and the drywall that will need to be sealed with spray foam or caulk

This fan has noticeable gaps between the fan box and the drywall that will need to be sealed with spray foam or caulk

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Right – The exhaust fan duct is sealed to the fan with mastic and the fan opening is covered with cardboard to keep out dust during construction.

Right – The exhaust fan duct is sealed to the fan with mastic and the fan opening is covered with cardboard to keep out dust during construction.

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The dark spots and streaks on this infrared camera photo clearly show cold air leaking in through gaps around a bathroom exhaust fan

The dark spots and streaks on this infrared camera photo clearly show cold air leaking in through gaps around a bathroom exhaust fan

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After cleaning the exhaust fan, the gap around the fan between the fan housing and the drywall should be caulked to stop air leakage from the house to the attic

After cleaning the exhaust fan, the gap around the fan between the fan housing and the drywall should be caulked to stop air leakage from the house to the attic

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This exhaust fan duct opens into the attic rather than exiting through the roof and mold has begun to form on the underside of the deck sheathing and on the rafter due to the moist air exiting the duct

This exhaust fan duct opens into the attic rather than exiting through the roof and mold has begun to form on the underside of the deck sheathing and on the rafter due to the moist air exiting the duct

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Whole-House Fans

Video

Video describing whole-house fans.

Bathroom and Kitchen Exhaust Fans (1)

Video

Video describing how to properly install a retrofit bath fan.

Bathroom and Kitchen Exhaust Fans (2)

Video

Video describing how to properly install a retrofit vent cap.

Mechanical Ventilation for Attached Garage

Guide

Guide describing how to install an exhaust fan in an attached garage to pull fumes out of the garage and to depressurize the garage with reference to the home.

Spray foam is used to fill the small gaps around this bath fan

Spray foam is used to fill the small gaps around this bath fan

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