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Air Sealing the Air Handler Closet

Guide

Guide describing the repair and reconfiguration of the air handler closet and platform when replacing the air handler.

Wrong: This return air plenum is not lined and air sealed

Wrong: This return air plenum is not lined and air sealed

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Air Seal HVAC Cabinet Seams

Guide

Guide describing air-sealing of the seams and holes in HVAC air handler and furnace cabinets.

Air Sealing Colorado Homes – 10.634

Reference

Fact sheet describing air-sealing concerns and remedies, including HRV/ERV installation, caulking, spray foam, and weatherstrip installation.

Wrong - Penetrations in walls for ducts should be air sealed to reduce air leakage.

Wrong - Penetrations in walls for ducts should be air sealed to reduce air leakage.

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Right: Use mastic to air seal the return air plenum and to seal around refrigerant lines coming from the slab in the floor of the return

Right: Use mastic to air seal the return air plenum and to seal around refrigerant lines coming from the slab in the floor of the return

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Right: Air seal all seams in the return air plenum before installing a new air handler

Right: Air seal all seams in the return air plenum before installing a new air handler

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Manually seal seams in the air handler box with foil tape

Manually seal seams in the air handler box with foil tape

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Wrong - The holes around the HRV ducting should be air sealed.

Wrong - The holes around the HRV ducting should be air sealed.

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Technology Solutions Case Study: Sealed Air-Return Plenum Retrofit

Case Study

Case study describing the retrofit of a leaky air handler.

Spray foam insulates and air seals the underside of the attic roof and walls.

Spray foam insulates and air seals the underside of the attic roof and walls.

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Right: The bottom of the air handler cabinet is well sealed to the return platform

Right: The bottom of the air handler cabinet is well sealed to the return platform

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Measure Guideline: Air Sealing Mechanical Closets in Slab-on-Grade Homes

Reference

Document covering two fundamental retrofit strategies for air sealing around air handling systems that are located within the living space in an enclosed closet.

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.

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

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

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

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

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

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The gaps around this HVAC boot have been air sealed with spray foam to limit air leakage between the conditioned space and the basement or crawlspace.

The gaps around this HVAC boot have been air sealed with spray foam to limit air leakage between the conditioned space and the basement or crawlspace.

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Air seal duct boot to ceiling by installing fiberglass mesh tape and mastic over seam

Air seal duct boot to ceiling by installing fiberglass mesh tape and mastic over seam

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Wrong - HVAC rigid metal duct seam needs to be air sealed with mastic or metal tape.

Wrong - HVAC rigid metal duct seam needs to be air sealed with mastic or metal tape.

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

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

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Wrong: The return plenum is not air sealed to separate it from the wall cavities and it should not be used for storage

Wrong: The return plenum is not air sealed to separate it from the wall cavities and it should not be used for storage

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Wrong: Open wall cavities in the un-air-sealed return plenum connect the plenum to attic spaces

Wrong: Open wall cavities in the un-air-sealed return plenum connect the plenum to attic spaces

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The gap between the duct boot and the drywall is air sealed by covering the seam with fiberglass mesh tape and mastic.

The gap between the duct boot and the drywall is air sealed by covering the seam with fiberglass mesh tape and mastic.

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The seam between this duct register and the wood flooring is sealed with caulk to prevent air leakage into the house from the crawlspace below.

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HVAC equipment should never be exposed to the garage; instead, locate them in air-sealed closets, with weatherstripping, spring-loaded hinges, and mastic.

HVAC equipment should never be exposed to the garage; instead, locate them in air-sealed closets, with weatherstripping, spring-loaded hinges, and mastic.

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This typical dropped ceiling hallway chase shows a complicated air sealing scheme where chase ceiling drywall meets sidewall top plates

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For homes with heating registers in the ceiling or floor, air seal where the duct boots meet the ceiling drywall or the flooring to prevent heat loss around the register.

For homes with heating registers in the ceiling or floor, air seal where the duct boots meet the ceiling drywall or the flooring to prevent heat loss around the register.

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Wrong - Hole in duct is not sealed and duct joint to subfloor is not sealed.

Wrong - Hole in duct is not sealed and duct joint to subfloor is not sealed.

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Connection in place but not sealed

Connection in place but not sealed

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