Question:

I noticed this summer that I’m getting a lot of hot air from the attic space.  I have a space of about 1-2 inches around the furnace exhaust pipe where it enters the attic through the ceiling drywall. What can I use to seal this space?  If I pack insulation around this I think it will burn.  I don’t think this is a double insulated pipe, more likely just a single layer pipe and it gets pretty hot. Can I buy a collar to fit around the pipe near the ceiling? Thanks, Jim

Response:

If that is singlewall KD, I would be more worried about the 1-2 inch space not being LARGE enough. Take a look before you get carried away, and make sure you have no signs of scorching around the area. As far as sealing it….you can get a stand off, rather, you should ALREADY have a standoff that is supporting the pipe there..if not, you may want to have one installed..there needs to be SOME airspace there, and you will not get as much hot air down from the attic from that one opening as you think. If anything, hot air will rise into it and leave via the gable/rafter vents. Also…if this is in, say a closet, and its obviously a gas or oil fired furnace, where is your make up air, or combustion air coming from??????  If you do not have a source of combustion air for the furnace, other than the air in the home, LEAVE the opening as it is. — www.carolinabreezehvac.com

– Hide quoted text — Show quoted text – I noticed this summer that I’m getting a lot of hot air from the attic space.  I have a space of about 1-2 inches around the furnace exhaust pipe where it enters the attic through the ceiling drywall. What can I use to seal this space?  If I pack insulation around this I think it will burn.  I don’t think this is a double insulated pipe, more likely just a single layer pipe and it gets pretty hot. Can I buy a collar to fit around the pipe near the ceiling? Thanks, Jim

Response: