if its a problem that just started happening try different filters. maybe your filter is dirty and your duct might be popping.
I have a Bryant Plus 80 gas furnace. Everytime the unit shuts down there is a loud bang. I am not sure if it is a metal on metal sound but that may be what it is. Anyone know why this may happen? It is annoying and wakes up our baby at times (the furnace is in the hall across from the room). I am sure it is something that probably needs to be checked out by a pro but I thought I would ask anyway. Any help or direction would be greatly appreciated.
if its a problem that just started happening try different filters. maybe your filter is dirty and your duct might be popping.
gahh
Sounds like "oil canning", call a local hvac company and they can cure it...
Check your air filter. Its probally the return trunk popping out after the blower shuts off. It would also be a good idea to brace the return trunk to help prevent this noise.