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Duct insulated with a minimum of R-8 insulation

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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.

The duct for this exhaust fan is properly routed through the roof and the duct is insulated

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Ducts Encapsulated in Spray Foam and Buried in Attic Insulation

Video

Video describing various ways to bring HVAC ducts installed in an attic within the thermal envelope of the home by insulating the attic or by covering the ducts with spray foam and burying them in fibrous insulation.

Wrong: Ductwork is not fully encapsulated with ccSPF insulation. The duct jacket is still fully visible at sections of the duct

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Spray foam insulation used for raised ceiling duct chase

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Spray foam insulation used for raised ceiling duct chase.

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The attic duct chase insulated and sealed to the attic floor with spray foam

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Right: Ducts are completely buried beneath insulation to the depth specified in the plans

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Wrong: Ducts are held above the ceiling plane with strapping to provide a good angle into top-entry boots. Once the ceiling insulation is added, this duct will protrude from the ceiling insulation and will not be buried

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Standard 2 in. by 4 in. stud secures duct chase - made of rigid insulation in this example

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Buried ducts are laid on the floor of a vented attic then covered with spray foam and blown attic floor insulation

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Right - Spray foam insulation has been sprayed onto the underside of the sloped roof and the gable end wall to provide a sealed, insulated attic for housing the HVAC ducts

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Right – Spray foam insulation is sprayed on the underside of the roof deck to provide a conditioned space in this low attic for the HVAC ducts.

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The spray foam-insulated attic provides a temperate place for the ERV ducts, which provide filtered fresh air to every room in the house.

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Right – Spray foam air seals and insulates the walls including the walls behind the fireplace and covers the underside of the roof deck of this mixed-dry climate home to provide an insulated attic space for HVAC ducts.

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Spray foam insulation is applied along the underside of the roof deck to provide a conditioned and non-vented attic space for ducts and air handlers.

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The unvented attic is insulated along the underside of the roof deck with 7 inches (R-49) of closed-cell spray foam, providing vaulted ceilings and a conditioned knee wall space for ducting.

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Right - This new sealed attic has 5.5 inches (R-20) of spray foam insulation along the underside of the roof deck providing a conditioned attic space for the heating and cooling ducts.

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A floor cavity between the first and second floor can provide a conditioned space for HVAC ducts if the rim joists are insulated and air sealed, if sufficient space is available, and if open-web floor joists are used

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Encapsulated Ducts

Video

Video describing air sealing and insulation for encapsulated ducts.

Encapsulated Ducts

Guide

Guide that illustrates how and when to encapsulate ductwork in unconditioned attics, increasing the R-value of duct insulation, mitigating condensation issues, and reducing air leakage.

Diagram of buried ducts

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Ducts in Raised Ceiling Sections

Guide

Guide describing method for designing and installing ducts in a raised ceiling chase.

Ducts in Dropped Ceilings

Guide

Guide describing method for installing ducts in a duct chase in a dropped ceiling.

Burried and encapsulated ducts in a ceiling plane

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Air Sealing Duct and Flue Shafts

Guide

Guide describing how to air-seal duct and flue shafts.

Encapsulated ducts are sprayed with ccSPF in an unconditioned attic

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Wrong: Ducts are held from the rafters with strapping and a large beam prevents ducts from properly lying on the ceiling plane

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Compact Buried Ducts in a Hot-Humid Climate House

Reference

Report on heating and cooling air-distribution ducts that are insulated, installed close to the ceiling in a vented attic and covered with attic insulation to minimize energy loss.