What is the best insulation for AC ducts?

fiberglass insulation
When insulating HVAC ductwork, use a foil, faced fiberglass insulation with an R-6 or higher R-value. Use the type of metallic foil duct tape recommended by the insulation manufacturer to seal and hold the insulation in place.

Does AC ductwork need insulation?

As you consider adding insulation, first be sure the duct system is delivering proper airflow. Insulating a leaky or undersized duct system is a waste of money.

How do you insulate old AC ducts?

Use a utility knife to cut foil-faced fiberglass insulation to the proper size. Wrap the insulation around the duct, and then pinch the seam closed. Secure the insulation with short strips of foil tape. Apply a long strip of foil tape along the seam in the insulation.

Can you insulate around air ducts?

Air ducts typically are not insulated, creating costly heating and cooling losses. You can insulate the round air ducts serving your rooms with standard insulation batts or special-purpose duct insulation. Insulating your air ducts can save 10 percent to 30 percent on energy bills while improving comfort.

Which insulating material is used in ductwork?

Elastomeric insulation sheets provide an effective, reliable, clean and healthy choice for the thermal and acoustic insulation of air ducts.

What R-value do I need for ductwork?

R-value of 3.5 is required for buried ductwork and ducts installed in an unvented attic with roof insulation or in an unconditioned space (including both ventilated and unventilated crawlspaces). There are no R-value requirements for ductwork installed in an indirectly conditioned space.

Should exposed ductwork be insulated?

A: Depending on the climate and the ducts’ location, it may not be necessary to insulate them. The ducts are exposed to the same cold, heat and humidity that exist on the outside. Insulating them is essential in colder climates, optional in milder ones and necessary in humid climates to prevent condensation.

Does exposed ductwork need to be insulated?

How much duct insulation do I need?

The basic recommendation from insulation contractors is that you should add one to three inches of insulation to your ductwork. Here are the relative values: 1 inch of insulation: R-value of 1.9. 1.5 inches of insulation: R-value of 3.5.

How do I stop my AC ducts from sweating?

Wrapping your AC ductwork is an effective way to prevent condensation. Duct wrap has a foam insulation inner layer and a foil outer layer. Cleanly wrap it around the AC duct and fasten with duct tape near the joints.

What R-value is flex duct?

For example, a six-inch diameter, nominal R-8 flex duct has an actual R-value of only 5.62 not counting surface films. With the film resistances the total R-value of 6.45 is 19% less than the nominal value. For R-11 ducts (six-inch diameter) the R-value with films is only 7.81, 29% less than the nominal value.