How Does a Wood Furnace Paired With a Gas Furnace Work?

[MinnesotaNative]

Hello All. Great forum you've got here!

I spent some time researching this but couldn't find the answer so thought I'd ask here.

I am about to purchase a home that has a newer high efficiency LP furnace as well as a wood burning furnace (says 'Hot Shot' on the cast iron door) along side it. It looks as though they are both connected to the same ductwork. There is (actually was) also a wood burning fireplace connected to the same system but, due to the unfunctional location of the fireplace, it is being removed.

My question is, how do these wood burning furnaces function in tandem with the LP furnace? The current home owner has never used the wood furnace and is not sure how it works either. Since there are tons of wood available in the area as well as a great below-ground woodroom just steps away from this furnace, I am really hoping that it's a good thing to have and that it will help to reduce heating costs for us.

 

[STIHLY DAN]

Take a few pics and post them, also tell us a little about thermostat and wiring. Not exact just little things like any at all, or a wire from furnace to furnace. There are a few different ways to install them and many more ways to control.

 

[KindredSpiritzz]

they don't really work in tandem, they just share the same warm air duct work to heat the home. You only run one or the other at a time and each should have its own separate chimney flue. The wood furnace should have back draft dampers installed somewhere between the furnace itself and the duct work to prevent the gas furnace from blowing air back into the wood one. Depending on the set up sometimes the gas furnace has a back draft damper to prevent the wood furnace from pushing hot air back into that. Least thats how mine works. Mine doesnt have a thermostat or any connection to the gas furnace except for the warm air ducting.

 

[KindredSpiritzz]

Heres a picture of mine. gas furnace on the left, wood furnace on the right. White pipes are gas furnace exhaust out the side of the house. Silver pipes are the warm air connection to the duct work and the black pipe way in the back is the stove pipe to the chimney. Cold air filter box is on the floor behind the stove and it pulls air in from the main floor thru the vents under the steps. I don't even turn on my gas furnace until i run out of wood, which this winter was a couple days ago.