Installing Duct Wrap Reflective Foil Insulation

Using reflective foil duct wrap insulation to create a radiant barrier around your duct work is one of the easiest DIY projects you can do to improve the performance of your heating and/or cooling system. Every minute HVAC systems run without effective insulation, your ducts leak valuable energy.

Properly insulating your ducts to create a radiant barrier can help stop radiant heat flow resulting in improved efficiency and less demand on your furnace or air conditioning units. This results in longer equipment life and lower utility bills.

Installing a radiant barrier using reflective foil insulation designed for duct applications is a relatively easy project if you can follow a few steps. First, decide how to run the insulation around the ducts. Create a sketch if you need to. This allows you to incorporate your measurements and identify problematic areas. You will save these harder areas for last.

1.      Place a string around the largest common section of your duct and get a measurement to determine the width of insulation you will need. Duct wrap reflective foil insulation comes in sizes measuring between 24-48 inches wide and from lengths as long as 125 feet.

2.      Add an extra ten inches width to your measurement for ordering purposes. The insulation must be wide enough to accommodate the addition of spacers. Using spacers to create an airspace helps achieve higher values, up to R-6. The other lower r-value option is to wrap the duct with no spacers. 

3.      Order an appropriate amount of insulation and reflective foil tape to complete the project. Duct wrap projects generally require more tape than other reflective foil insulation projects because tape is used more often in problematic spots to create a seal around the insulation. Many times these areas are not perfectly shaped and the extra tape helps to join and seal various pieces of insulation.

4.      Apply Spacers: Spacers are applied approximately every 4 feet. They should also be used whenever two pieces of insulation are joined together. This guarantees an adequate airspace throughout your project further increasing your energy gains.

5.      Create spacers by cutting three inch wide strips of material and wrapping them around the duct at predetermined locations.

6.      Note: Duct wrap insulation kits make applying spacers much faster. Kits contain L- shaped spacers. These are applied to all four sides of the ducts. These spacers are four feet long allowing you to cover distance much faster. Using insulation kits also guarantees a spacer where one piece of insulation stops and another one starts.

7.      Install Insulation: Cut insulation to length for specific area. Wrap duct with insulation. Tape seam. If insulation is too long it can be trimmed with razor knife or utility scissors. 

8.      Continue installing insulation until ducts are wrapped.

9.      Complete areas where obstacles were. Figure out the best way to wrap the area. Try to incorporate a gap for airspace when possible. Ensure all seams are taped. The key to these areas are to get them wrapped and taped. Aesthetics are secondary.

Walk entire duct run and ensure all portions are wrapped. Tape and seal all seams where any pieces of insulation meet. Make sure all seams are sealed. 

You have now created a radiant barrier surrounding your duct work that will reflect radiant heat, a major source of energy loss. By using spacers, an airspace has also been created that will allow the reflective foil insulation to work at its optimal level.

Rest assured that in the winter heating months, heat is being delivered where you want it, in your living space.  Much less is radiating uselessly out of your ducts. In the summer cooling months, radiant heat gain is blocked from entering your ducts allowing your air conditioning to work as efficiently as possible.