Think about it. The heat in the furnace room must go somewhere. If the
room is too well insulated it will get hotter and hotter until the heat loss
equals the heat from the furnace walls. This will cause the furnace to be
hotter, maybe shortening the life of the motor. You might put a small
opening in the inlet duct to draw house air into the furnace, making sure
there is space under the door for the air to flow in.


"TKM" wrote in message
...
What kind of insulation materials should I use to insulate the hot-air
pipes
and ceiling in a furnace room?

The house is about 5 years old with 6 inches of blown-in cellulose
insulation in the walls and ceilings. The furnace room is on the second
floor and has a finished drywall ceiling and walls. But the room is very
warm during the winter and snow on the roof above the furnace room melts
before the snow on the rest of the roof.

I've sealed the furnace pipe joints with mastic to stop hot-air leaks; but
now I'd like to wrap the pipes with insulation and add a layer of ceiling
insulation inside the room and maybe the outside wall too.

TKM