Soundproofing a furnace closet

[horsepit]

I am looking for a soundproffing material to line the inside of furnace closets with. I've been using duct board with limited success. I saw a foam, waffle looking product that seems to work better, but I can't track down a supplier. Does anyone have any suggestions?

[Dave Brown]

Keep in mind that you need to allow air into the furnace closet for combustion of the furnace and water heater. But, if i were going to insulate the furnace door and surrounding walls of the closet, id use 2" thick dense pink styrofoam board available at Home DePot keeping it at least 2" away from the furnace/flue pipes. You can buy a big sheet of this and its cheap.  I used this to make a partition in my workvan so i didnt hear my tools making noises in the back --- it is very effective as a sound barrier as well as an insulator.

[supersoundproofing]

There are MUCH better materials to use than Styrofoam- (a good thermal insulator, but...)

Use the soundproofing foam at
http://www.soundproofing.org/sales/prices.html for best results.  The thicker the better!