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Ducts are properly insulated and supported without compressing the insulation

Ducts are properly insulated and supported without compressing the insulation

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Ducts are insulated but strapping is compressing the insulation therefore reducing the R-value

Ducts are insulated but strapping is compressing the insulation therefore reducing the R-value

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Duct and HVAC Insulation

Reference

Information sheet with HVAC duct insulation, testing, maintenance and performance information.

Sealed and Insulated Flex Ducts

Guide

Guide describing how to air seal and insulate flex ducts.

Ducts Buried in Attic Insulation

Guide

Guide describing the practice of burying HVAC ducts in loose-fill insulation on the attic floor.

Ducts Buried in Attic Insulation and Encapsulated

Guide

Guide describing approaches to burying and encapsulating ducts in unconditioned attics to increase the overall R-value of duct insulation.

Air seal and insulate flex ducts

Air seal and insulate flex ducts

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Duct insulation is installed over boot

Duct insulation is installed over boot

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Insulation does not cover boot and is not sealed

Insulation does not cover boot and is not sealed

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Duct is located in unconditioned space and is not insulated

Duct is located in unconditioned space and is not insulated

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Sealed and Insulated Fiber Board Ducts

Guide

Guide describing how to air seal and insulate fiber board ducts.

Insulation does not cover boot and is not sealed

Insulation does not cover boot and is not sealed

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Insulation does not cover boot and is not sealed

Insulation does not cover boot and is not sealed

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No insulation installed in cavity and not air sealed

No insulation installed in cavity and not air sealed

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Duct is located in unconditioned space and is properly insulated

Duct is located in unconditioned space and is properly insulated

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Measure Guideline: Sealing and Insulating Ducts in Existing Homes

Reference

Report describing the sealing and insulating of HVAC duct systems in existing homes.

Prescriptive Path: Supply ducts in unconditioned attic have insulation ≥ R-8. Performance Path: Supply ducts in unconditioned attic have insulation ≥ R-6

Prescriptive Path: Supply ducts in unconditioned attic have insulation ≥ R-8. Performance Path: Supply ducts in unconditioned attic have insulation ≥ R-6

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Pull the insulation and outer liner of the flex duct over the collar to come in full contact with the liner and insulation of the trunk line or fitting and tape in place

Pull the insulation and outer liner of the flex duct over the collar to come in full contact with the liner and insulation of the trunk line or fitting and tape in place

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Boot has been covered with insulation and sealed with mastic

Boot has been covered with insulation and sealed with mastic

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Inadequate amount of insulation installed with compression, misalignment, and voids

Inadequate amount of insulation installed with compression, misalignment, and voids

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Trunk to duct connections are properly insulated and have been sealed with mastic

Trunk to duct connections are properly insulated and have been sealed with mastic

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Wrong - Flex duct resting on floor compressing insulation and causing condensation

Wrong - Flex duct resting on floor compressing insulation and causing condensation

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Seal all joints and seams in the metal ductwork with mastic before installing insulation

Seal all joints and seams in the metal ductwork with mastic before installing insulation

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Cleaning Fibrous Glass Insulated Duct (Ductboard / Duct Board) Systems - Recommended Practices

Reference

Manual showing duct cleaning contractors how to identify the different types of insulated air ducts, how to open each type for access by cleaning equipment and personnel, how to close and seal openings after cleaning.

Wrong - Duct insulation and vapor barrier do not cover all of the flex duct.

Wrong - Duct insulation and vapor barrier do not cover all of the flex duct.

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Wrong - Flex duct insulation is overly compressed in 3 ways; Zip-tie fastener is over the insualtion not under the insulation at the duct boot collar, duct turning radius is too tight, and support strap is too tight.

Wrong - Flex duct insulation is overly compressed in 3 ways; Zip-tie fastener is over the insualtion not under the insulation at the duct boot collar, duct turning radius is too tight, and support strap is too tight.

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Right – Flex ducts are properly supported with straps that don’t pinch the insulation; closed-cell spray foam will be applied to the underside of the roof deck of this hot-humid climate home to provide an insulated attic space for the HVAC ducts.

Right – Flex ducts are properly supported with straps that don’t pinch the insulation; closed-cell spray foam will be applied to the underside of the roof deck of this hot-humid climate home to provide an insulated attic space for the HVAC ducts.

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Wrong- A tie strap should not be used over the duct outer liner because it can compress the insulation. Tuck in the fibrous insulation and seal the outer liner to the connecting duct with mastic or foil tape (Steven Winter Associates 2013).

Wrong- A tie strap should not be used over the duct outer liner because it can compress the insulation. Tuck in the fibrous insulation and seal the outer liner to the connecting duct with mastic or foil tape (Steven Winter Associates 2013).

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Cavity used for return is not insulated and is not air sealed, which will pull in air from outside

Cavity used for return is not insulated and is not air sealed, which will pull in air from outside

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All other supply ducts and all return ducts in unconditioned space have insulation ≥ R-6

All other supply ducts and all return ducts in unconditioned space have insulation ≥ R-6

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