Insulating Your Heating Ducts

You’d be surprised how much heat is lost in the heating pipes and ducts running around your home. Without insulation, areas and rooms that never get used end up getting all the heat. Easily, one of the most energy-efficient ways to save on costs is with simple fiberglass duct insulation.

Find out how much insulating material you will need by measuring the distance around each duct and multiplying that number by the total length of duct you would like to insulate. It might be wise to order a few extra meters to account for mistakes and overlaps that will occur during fastening. Before you start, repair all air leaks in your system; a temperature-resistant caulk (like silicone) is good, but duct tape will do just fine as well.

Pick up some vinyl or foil-backed fiberglass insulation. Regular-faced insultation will work as well, with an added bonus of being less expensive but still with a decent R-value (the ability to retain heat flow). Cut your fiberglass to fit and secure over the supply ducts with staples, wire or duct tape. If using tape, don’t be stingy! Wrap the tape completely around the duct, overlapping several times. There should be no exposed fiberglass or joints, regardless of the sealing method you use, as you want to eliminate as much air flow beneath the insulation as possible.

One very important safety issue is to never insulate your return ducts. Because of the extreme heat, you should never place pipe insulation within 3 feet of the heating system or exhaust flues. While not as hazardous but will save you a headache later, keep damper control handles accessible and remove any labels on the ducts and reposition them on the outside of your insulating layer.

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One Response to “Insulating Your Heating Ducts”

  1. Amanda October 1, 2010 at 12:57 pm #

    Inspect your heat ducts for air leaks. If you find an air leak, seal it with fasteners, mesh and mastic, or foil tape. Don’t use duct tape – it doesn’t hold up over longer periods of time. It is generally recommended that you use at least an R-4 insulation (the higher the better) to insulate heat ducts in a crawl space. It’s important to note that different types and brands of insulation have different R ratings.

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