Why Radiant Barrier Foil Duct Wrap Insulation?
This entry was posted on December 28, 2009.
Insulating your duct work is an easy energy saving project that can make your home more efficient. The purpose of this post is not to show you how to insulate your ducts, but why to insulate them.
First, duct work used for heating and cooling should be checked to ensure the system is airtight. Any leaking areas are huge sources of energy lost and should be fixed promptly.
Now, the reason you insulate around your duct work with reflective foil insulation is to stop the transfer (loss or gain) of radiant heat into or out of your ducts.
For example, picture your duct work in the cold, winter months delivering 70° air into your living space. Regardless of whether the duct work is in the attic or basement, the temperatures in these areas, especially in attics are well below 70°.
Let's say the attic temperature is 25° and you are asking your heating system to deliver 70° temperature. The system at the start is pushing approximately 135° air. Let's use 90° which would occur somewhere in the middle of the run.
The difference between the 25° attic and the 90° testing point is 65°. That is 65° of radiant heat that constantly wants to be exchanged or lost in your case. Radiant barrier foil insulation when installed correctly blocks 96% of this radiant heat exchange.
To use the example again, as the duct constantly radiates or loses heat to the cold attic lowering your energy efficency, insulating with reflective foil insulation reflects 96% of this heat back to the duct work stopping this energy loss.
Depending on your installation method you can achieve an R-value of R-2, R-4, or R-6.