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Air seal at duct soffit

CAD File

Air Seal HVAC Cabinet Seams

Guide

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

Air Sealing Duct and Flue Shafts

Guide

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

Duct boots and other ceiling penetrations are air-sealed using spray foam

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Form an insulation dam of sheet metal around a flue pipe in the attic after air sealing around the pipe with sheet metal and fire-rated caulk or canned foam

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Form an insulation dam of heat-resistant insulation with at least 3 inches of clearance around a flue pipe in the attic after air sealing around the pipe with sheet metal and fire-rated caulk or canned foam

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Right- This flue pipe has been air sealed with sheet metal and fire-rated caulk and an insulation dam has been constructed to keep insulation from touching the hot flue pipe

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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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Sealed Attics?

Reference

Article describing how insulating and air sealing unfinished attic spaces can lead to reduced energy bills in some homes.

Raised ceiling chase sealed with drywall mud

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Install sheet metal to cover the gaps around a flue pipe in the attic; attach with screws or heavy staples, then seal seams with fire-rated caulk or foam

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Wrong: open wall cavity connected to this return air plenum is allowing cellulose attic insulation to be pulled into the furnace

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Furnace and chimney flues often have large gaps around them that allow air leakage from the home into the attic.

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Wrong: This wall cavity is open to the attic allowing unconditioned, attic air to enter the HVAC system, bypassing the filter, and degrading system life and performance

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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

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Encapsulated Ducts

Video

Video describing air sealing and insulation for encapsulated ducts.

Existing Whole-House Solutions Case Study: Deep Energy Retrofit in the Pacific Northwest

Case Study

Case study describing a whole-house, deep energy retrofit project in the marine climate.

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.

New Whole-House Solutions Case Study: Tom Walsh & Co., New Columbia, Portland, OR

Case Study

Case study describing a new construction building project of 20 homes that earned HERS scores that represent greater than 50% energy savings in heating and cooling over the 2004 IECC.

Second layer of rigid insulation is adhered with foam

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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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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.