I just opened up the air return grille connected to my HVAC system and discovered something unusual along with a lot of dust. There's this black mat that looks like it's made of half-inch batt insulation. Can anyone tell me what this is called and what its purpose is? It's in pretty rough condition, and I'm trying to decide if I need to replace it or if it can just be removed. For some context, my HVAC system is on the other side of the wall where I've pointed out with red arrows, and the black mat in question is marked with a green arrow. The house was built in 1999 and the ductwork runs through the attic using insulated flexible hoses, which are about a foot in diameter.
1 Answer
That black mat is actually duct board, which is typically made from fiberglass. It's often used to create custom ductwork. While it's not a must-have part of your system, it might have been installed to help reduce noise since your air handler is located in a closet. In my experience at an HVAC company, we installed it occasionally for that reason.
Thanks for the info! If I do decide to replace it, can I use a piece of EPS rigid foam insulation instead?