Insulating Heating Ducts In Attic

Because the moving air is in the ductwork for only a short period of time it does not need the insulation r value the attic floor requires.

Insulating heating ducts in attic.

When the attic is 20 f that insulation is addressing a delta t of 50 f. How to insulate your central air heating ducts 1. Other times insulation may be on the outside. Insulating exposed heating ducts in attics basements and under subfloors can improve the energy efficiency of a heating system.

Made from 1 to 2 inch thick sheets of rigid glass fiber and coated with an aluminum laminate for a moisture air barrier duct board comes in sections that fit together like metal ducts. R 8 duct insulation 5 227 btu hour. When insulating hvac ductwork use a foil faced fiberglass insulation with an r 6 or higher r value. Don t use standard cloth duct tape on hvac ductwork since the adhesive won t hold up to extreme temperatures.

Plan to pull up the flooring and layer new insulation on top of the old. The duct insulation should include a vapor barrier cover. Check the speed of the blower motor on the furnace. Press a continuous strip of foil tape to all longitudinal seams along straight runs of duct.

Inspect the span of ductwork to be insulated. According to rightsuite the software we use the supply ducts have about 560 square feet of surface area and the return ducts 101 square feet. If necessary switch the wires to reduce the blower to its lowest. But if the floor is covered in plywood you can t stuff enough insulation beneath it to do the job sufficiently not even in warm climates.

Install ductwork so that it is in direct contact with i e laying on the ceiling and or truss lower cords. After all most new homes have r 49 insulation on the attic floor holladay continues. The existing metal ductwork in an older home may or may not have insulation. Look for signs of air leaks at seams or joints such as streams of dust.

But the air in the ducts is facing a delta t of maybe 100 f or 120 f a greater delta t. Purchase duct wrap insulation that complies with the 2009 international energy conservation code iecc standards. Duct board much like the duct liner is also a fiberglass product. When hvac ducts are installed in a vented attic in a dry climate bury the ducts in attic insulation to protect them from temperature extremes in the unconditioned attic space.

Use the type of metallic foil duct tape recommended by the insulation manufacturer to seal and hold the insulation in place. Because the simplest and cheapest way to insulate an attic is to add material to the floor. Sometimes the insulation is inside the ductwork. Use metal flex or fiber board ducts that are insulated to code.

Typical ducts install between a plenum or large supply duct and. Looking at the cooling side only the additional load would be. Duct liner isn t generally a diy installation and if your ducts already have liner you don t need to insulate the exterior. So logically the ducts deserve more not less insulation.