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Ventilation air inlets ≥ 2 ft. above grade or roof deck in Climate Zones 1-3 or ≥ 4 ft. above grade or roof deck in Climate Zones 4-8 and not obstructed

Ventilation inlet does not terminate high enough above the roof deck

Ventilation inlet is not near any exhaust outlets/contamination sources and is at least 2 ft. above the roof deck

Ventilation inlet is too close to exhaust outlets and does not extend at least 2 ft. above the roof deck

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.

Publication Date

Thu, 09/30/2021 - 12:00

Support at Intervals for Flex Ducts

Guide describing how to hang ducts with supporting straps or saddles to adequately support ducts so they do not sag and are not pinched or compressed in a manner that would cause damage to the ducts, the duct insulation, or the duct air barrier covering.

Ducts Buried in Attic Insulation and Encapsulated

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

Ducts in Dropped Ceilings

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

Compact Air Distribution

Guide describing design and installation of compact duct systems for central heating and cooling systems.

Ducts in Raised Ceiling Sections

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