Insulate heating ducts for sound????
I have heating ducts running along the ceiling of my basement. When I have the TV or stereo on in the basement, these metal ducts transmit the sound to the whole house. Any ideas on insulating them to reduce this?
My ideas so far are a plywood box with fiberglass underneath, a frame and drywall also with insulation underneath, or a box built out of rigid foam. I have very little headroom so size is an issue.
Thanks for any help.
Paul
Replies
One thing you need to do is to stiffen and dampen the metal itself, since the sound travels along the metal. There's probably a commercial product available, but gluing on old linoleum scraps will work fairly well.
In the automotive aftermarket there are a number of sound deadening products that are used to make the inside of a car quieter. They are usually sort of a rubberized sheet with a sticky back, you cut it into pieces and stick it on the floorboards, door panels, etc. You don't necessarily need to cover the entire surface, I think that strips of the stuff will do nearly as much good. It helps dampen the vibrations in the sheet metal, so I suppose it would do the same thing on furnace ducts. You can check at a local auto stereo shop for it, or search online. One good brand is Dynamat, at http://www.dynamat.com/
Here is another product:
http://www.acousticalsolutions.com/products/blocking/duct_wrap.asp
Expensive! But I may need it too... Home theaters in basements...
Billy