Insulating Heating Ducts In Attic

Plan to pull up the flooring and layer new insulation on top of the old.

Insulating heating ducts in attic.

Use a paintbrush to apply duct mastic to the joints where an elbow. Use metal flex or fiber board ducts that are insulated to code. Other times insulation may be on the outside. All the ducts are in the attic.

But the air in the ducts is facing a delta t of maybe 100 f or 120 f a greater delta t. The duct insulation should include a vapor barrier cover. The existing metal ductwork in an older home may or may not have insulation. 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.

Insulating exposed heating ducts in attics basements and under subfloors can improve the energy efficiency of a heating system. For an added layer of protection you can apply duct mastic to the tape and duct. Sometimes the insulation is inside the ductwork. So logically the ducts deserve more not less insulation.

Use the type of metallic foil duct tape recommended by the insulation manufacturer to seal and hold the insulation in place. 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. Duct liner isn t generally a diy installation and if your ducts already have liner you don t need to insulate the exterior. If necessary switch the wires to reduce the blower to its lowest.

Check the speed of the blower motor on the furnace. How to insulate your central air heating ducts 1. Looking at the cooling side only the additional load would be. Inspect the span of ductwork to be insulated.

When the attic is 20 f that insulation is addressing a delta t of 50 f. 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. Press a continuous strip of foil tape to all longitudinal seams along straight runs of duct. Purchase duct wrap insulation that complies with the 2009 international energy conservation code iecc standards.

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. Look for signs of air leaks at seams or joints such as streams of dust. Because the simplest and cheapest way to insulate an attic is to add material to the floor. Don t use standard cloth duct tape on hvac ductwork since the adhesive won t hold up to extreme temperatures.

R 8 duct insulation 5 227 btu hour. After all most new homes have r 49 insulation on the attic floor holladay continues. Typical ducts install between a plenum or large supply duct and. Duct board much like the duct liner is also a fiberglass product.