When to Use Insulated Ducts?

Unfinished Areas

• Ductwork often runs through parts of the home that are not heated by a central heating system or cooled by a central air conditioner. These parts of the home -- basements, crawl spaces and attics -- tend to get very cold in the winter and warm in the summer, creating an extreme temperature differentials between the heated or cooled air moving inside the ducts and the air outside the ducts. This temperature differential creates condensation and can reduce the overall efficiency of your heating or cooling system, so it is important to insulate any ducts that run through these unfinished parts of the home.

Finished Areas

• It's also important to insulate ductwork that moves through finished rooms in the home. These areas are not as prone to inefficiencies through air loss, but condensation is much more likely to form on these ducts, which can lead to moisture problems in hard-to-access areas. Insulating these ducts will help prevent these moisture and condensation problems, but ducts in finished areas of the home generally require much less insulation than those in unfinished areas.

Installation Tips

• Rigid fiber board insulation is typically recommended for insulating ductwork. You should know what R-value you should aim for when installing insulation around your ductwork. Depending on geographic and climatic differences, ducts may require anywhere from R-2 to R-11 insulation. Ducts in basements and crawl spaces can typically be insulated to lower R-values than those in attics.

The Importance of Duct Sealing

• Sealing openings in your ductwork should be part of your overall insulation strategy. However well insulated a particular duct is, it will continue to lose air and diminish the efficiency of your heating and cooling system if openings in the ductwork are not properly sealed. Do not use duct tape to seal ducts; duct tape offers only temporary seals and is not as effective at creating airtight seals as mastic sealant or metal tape.