Image Wrong - Duct insulation and vapor barrier do not cover all of the flex duct. Publication Date Fri, 12/07/2018 - 12:00
Image Wrong – Insulation should not be pinched where flex ducts connect to the trunk duct as compression of the insulation here can lead to cold spots and condensation on the duct surface. Publication Date Fri, 12/31/2021 - 12:00
Image Wrong - Duct insulation and vapor barrier do not cover all of the flex duct. Publication Date Fri, 12/07/2018 - 12:00
Image All other supply ducts and all return ducts in unconditioned space have insulation ≥ R-6 Publication Date Fri, 10/28/2011 - 12:00
Image Right – Batt insulation provides additional insulation for the home’s main duct chase. Publication Date Mon, 09/30/2019 - 12:00
Image Prescriptive Path: Supply ducts in unconditioned attic have insulation ≥ R-8. Performance Path: Supply ducts in unconditioned attic have insulation ≥ R-6
Image Wrong: Ductwork is not fully encapsulated with ccSPF insulation. The duct jacket is still fully visible at sections of the duct
Image 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. Publication Date Sat, 01/19/2019 - 12:00
Image If a dropped soffit is used to house a duct, the soffit space must equal the duct diameter plus the insulation thickness
Image Right – Rigid foam is installed behind HVAC ducts to provide additional insulation to the ducts which are installed within the conditioned space. Publication Date Mon, 09/30/2019 - 12:00
Image 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
Image To attach the flex duct to a main trunk duct or any other connection, the flex duct is pulled over the connecting collar at least 2 inches past the raised bead, then the insulation is pulled back
Image Right – Plastic tenting increases the height of the insulation above ducts that are located in the attic. Publication Date Mon, 09/30/2019 - 12:00
Image A ducted central return brings air from central return registers back to the air handler through insulated, air-sealed ducts Publication Date Thu, 03/09/2017 - 12:00
Image R-6 flexible duct has 2 inches of insulation around the inner liner so a 12-inch duct requires a 16x16-inch chase
Image 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
Image Because this ICF and spray foamed house is so well insulated, the HVAC system is smaller, the round metal ducts are smaller diameter, and the duct layout is more compact. Publication Date Wed, 01/01/2014 - 12:00
Image 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).
Image Wrong – Don’t use nails to fasten poly vapor barrier around flex ducts; it will allow moist air to reach the ducts where it could condense and ruin the insulation. Publication Date Tue, 04/13/2021 - 12:00
Image 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
Image A nylon draw band and tensioning tool are used to secure the inner coil of the pre-insulated flexible duct Publication Date Wed, 11/21/2012 - 12:00
Image A nylon draw band and tensioning tool are used to secure the inner liner of the pre-insulated flexible duct
Image Buried ducts are laid on the floor of a vented attic then covered with spray foam and blown attic floor insulation Publication Date Wed, 09/01/2021 - 12:00
Image Right – All supply ducts in this home were located in conditioned space; any return ducts that were located in the attic were insulated with closed-cell spray foam and buried in the blown-in attic insulation to prevent air leakage and heat loss. Publication Date Thu, 09/30/2021 - 12:00
Image If HVAC duct must be installed in an exterior wall, separate it from the exterior with at least R-6 of continuous rigid insulation
Image Right - the vapor barrier is extended up the sides of the piers in this crawlspace, which is sealed and insulated to house the HVAC ducts.
Image The main trunk line of the ducts runs within an insulated duct chase installed in a notch designed into the roof trusses that runs the length of the home to provide supply air directly to most of the home’s ceiling registers.
Image When wrapping metal ducts with insulation allow two inches of overlap and staple along the seam with outward clinching staples
Image 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
Image 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. Publication Date Fri, 12/31/2021 - 12:00
Image The sealed, insulated crawlspace is a clean, dry location to house the main floor heating ducts and also provides bonus storage space.
Image HVAC ducts, cavities used as ducts, and combustion inlets and outlets may pass perpendicularly through exterior walls but shall not be run within exterior walls unless at least R-6 continuous insulation is provided on exterior side of the cavity
Image Wrong - HVAC duct and flue are too close to wall and will be difficult to properly air seal and insulate around when ceiling is installed. Publication Date Fri, 03/17/2017 - 12:00
Image The spray foam-insulated attic provides a temperate place for the ERV ducts, which provide filtered fresh air to every room in the house.
Image Step 4. Install insulating sheathing and vertical furring strips on the retrofitted exterior wall; seal around pipe or duct with urethane sealant.
Image This Habitat for Humanity builder ordered roof trusses with a 2-foot by 2-foot notch next to the center post then lined the cutout with rigid foam to form an insulated central duct chase to bring the heating and cooling ducts within the conditioned space.
Image 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. Publication Date Thu, 09/30/2021 - 12:00
Image 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. Publication Date Thu, 09/01/2011 - 12:00
Image This whole house fan is suspended from rafters and connected to the intake grille by a curved insulated duct, greatly reducing vibration and noise in the occupied space Publication Date Sat, 01/01/2022 - 12:00
Image HVAC ducts can be encapsulated in 3 inches of closed-cell spray foam, then buried in R-49 of blown fiberglass insulation after the ceiling drywall is installed in the vented attic.
Image Right: This heat pump water heater is installed in a small space so the, intake air is ducted from an adjacent room; the water heater since on a pad of foam insulation and has a good drain line configuration but the waterpipes lack insulation Publication Date Wed, 02/14/2024 - 12:00
Image 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.
Image 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.
Image Wrong – These flex ducts are pulled taut, which is correct but they are inadequately supported with straps that are spaced too far apart and are too tight causing pinching of the insulation and turns are sharp rather than gradual.
Image 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 Publication Date Wed, 01/01/2014 - 12:00
Image Specially designed roof trusses come with a two-foot by two-foot notch cut next to the center post providing space to install an insulated duct chase inside the home’s conditioned space but above the normal ceiling height.
Image Advanced framing techniques including 2x6 walls spaced at 24 inches on center and ladder blocking at wall intersections allow more space for insulation in the wall cavities while open-web floor joists provide space between floors for ducting. Publication Date Mon, 01/01/2018 - 12:00
Image Collars that are specifically made for flexible duct have a raised bead to prevent the duct from slipping off
Image Encapsulated ducts are sprayed with ccSPF in an unconditioned attic Publication Date Thu, 08/01/2013 - 12:00
Image Wrong: Ducts are held from the rafters with strapping and a large beam prevents ducts from properly lying on the ceiling plane
Image Duct boots and other ceiling penetrations are air-sealed using spray foam Publication Date Wed, 09/29/2021 - 12:00
Image Right: Ductwork is installed in direct contact with lower truss cords. In this picture the main trunk is laying on the truss cords and branch ducts are temporarily held with strapping across truss cords. Ducts are well sealed with mastic
Image Wrong: Ducts are not laid across the lower truss cords or ceiling, but are hung from the rafters by straps. As a result, ductwork is not buried
Image Two pieces of flex duct are spliced together with a metal sleeve, nylon draw bands, mastic, metal tape, and more mastic
Image Cut fiber board with a red V-groove tool and a gray shiplap tool to create mitered corners and a shiplapped edge for duct sections
Image Right - The rigid metal HVAC ducting is installed between the floor joists rather than in an unconditioned attic or crawl space to minimize heat loss.
Image Right – R-25 of open-cell spray foam lines this new home’s attic ceiling, to protect HVAC ducts from heat and cold.
