I have a wood furnace that ties into the electric HVAC in my basement. I had the chimney sweep over today and he suggested rerouting the air supply for the wood furnace to make it more efficient.
Right now the wood furnace draws air from the return and it gets sucked (hopefully) into the warm air side of the supply duct after the filters. This is not very efficient and causes the cooling fan on the wood furnace to run constantly, running up my electric bill.
What I want to do is run the heat from the furnace back into the return and install a damper between the intake and exhaust ports in the return so that the HVAC fan will draw all air through the wood furnace when it is burning. This will also ensure that the air from the furnace is getting filtered. Achoo!
The return duct is 18"X11.5" ID. and I is sealed so I will have to cut an 8" hole for the hot air duct from the wood furnace and then somehow get an 11.5" wide piece of sheet metal through to act as my damper. How should I go about this? I'd like to keep it DIY. Drawing for clarity. Any help is greatly appreciated.