Insulate Return Ducts In Attic

Some insulation types offer high promises but fail to consistently perform in the field.

Insulate return ducts in attic. Covering ductwork with insulation. First seal the duct seams with mastic. R 8 duct insulation 5 227 btu hour. Or applying spray foam insulation to the outside of the duct.

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. That has kept the ventilator working but ted surmises the high. Is it ok to do it. Summer hasn t even arrived he notes in a post at gba s q a forum and when the temperature outside climbs to more than 95 f the temperature in the attic tops 120 f.

As you consider adding insulation first be sure the duct system is delivering proper airflow. Come up with a plan for insulating the underside of the ducts. Looking at the cooling side only the additional load would be. Be careful as you choose from the various insulation options.

Make sure that the rigid foam is secure. Purchase duct wrap insulation that complies with the 2009 international energy conservation code iecc standards that specify an r value of 8 for attic ducts and 6 for ducts located anywhere else. Hvac ductwork is typically visible in your attic especially flexible ductwork. Although both the attic floor and the ductwork are insulated ted recognizes the situation isn t ideal.

The two most common ways to insulate ductwork are wrapping the duct in a foil faced blanket. All the ducts are in the attic. Insulating a leaky or undersized duct system is a waste of money. I would use foil faced polyiso which is the easiest type of foam to tape and tape it securely 3.

If using this technique in a humid or marine climate the ducts must be encapsulated with spray foam before installing the blown insulation. If you need help deciding which type of insulation you need set up an energy consultation. Add additional sealant if necessary. Install loose fill insulation to cover the ducts and the attic floor to meet or exceed the code required r value for attic insulation.