Air ducts transport forced air through your house to regulate internal air temperature. However, poorly insulated duct work can result in increased heating and cooling expenses for your home. By adding or improving home insulation in this area, you can save money on your heating and cooling bills.

Improving air duct insulation after the duct work has been installed is a bit more difficult than having it done when the home is built. However, insulating duct work is a relatively low-cost improvement that can result in a significant upgrade in your home’s energy efficiency.

Improving Air Duct Insulation: The Basics

If you plan to improve heating duct insulation in your home, you will first need to seal the leaks or gaps with foil tape or duct mastic (a type of adhesive that is spread or sprayed on ducts). This will prevent air from leaking out as it passes through the duct on its way to a vent. The more airtight the duct work, the more efficient the air handling system. Ironically, it is not a good idea to use duct tape on ducts, as it has a tendency to dry out and come loose over time.

After you have sealed any leaks in your ducts, you can add duct insulation. You need duct insulation because the thin walls of the ducts conduct heat extremely well. As warm air passes through the duct work, a significant amount of heat can be lost before the air reaches the exit vent. The opposite can happen if the duct work is carrying cool air, with outside air warming the air in the ducts before it reaches the room it is meant to cool.

You will want to make sure that the ducts in the following areas of your home are insulated:

• Attic
• Basement
• Crawlspace
• Garage.

Installing Heating Duct Insulation

Heating and cooling air duct insulation comes in rolls of fiberglass batting called jackets. These jackets, or duct wrap, fit over the duct work and are secured with tape.

The insulation works best if the jackets are tight along the ducts. The jackets should be covered by foil on one side and fiberglass on the opposite side. The fiberglass will face the duct and the foil faces out, protecting the duct work and insulation from temperature fluctuations and moisture build- up.

Alternatives to the typical fiberglass jacket insulation include a foil or polyethylene heat wrap that insulates by reflecting radiant heat back into the duct work. Much like fiberglass, this wrap is rolled onto the duct work and secured with duct tape. This material is usually thin and flexible, making it easy to install and secure.