How To Insulate Sheet Metal Plenum

Plenum should be dry before external insulation is applied.

How to insulate sheet metal plenum.

Check the speed of the blower motor on the furnace. You can fasten and secure the ends of the batts with duct tape but that may cause the insulation to get spoiled. 38 to 102mm insulation boards fibrous glass insulation boards are also available for application to the outside of sealed sheet metal ducts housings and plenums. Check for air leaks sealing them helps your system more than just the condensation problem.

In this video this old house plumbing and heating expert richard trethewey helps a homeowner insulate his ductwork. Ductwork is typically insulated with foil or vinyl backed fiberglass insulation specially made for the application. Sheet metal ducts must first be tightly sealed resilient fibrous glass insulation thicknesses from 11 2 to 4 in. Use foil faced insulation batts to wrap up the pipes but see to it that the whole thing is properly covered and any previous layers are thoroughly overlapped.

Insulation used to externally insulate hvac ducts. Do not use rigid foam insulation unless you know what the temperature rating is. If you do insulate the plenum the irc does require you to use a vapor barrier on the exterior of the insulation or use duct insulation blankets with integral vapor barrier and tape the seam s. Press a continuous strip of foil tape to all longitudinal seams along straight runs of duct.