I have a house with a forced air electric furnace.

We've also got a wood-burning stove adjacent to the furnace. I didn't have it installed, and I want to understand if it's been done properly, and how to use it properly. The house is on a big plot of land and there's plenty of hardwood available for use in the stove.

Right now the hot air duct out of the wood stove is connected to the return air duct that leads IN to the electric furnace.
Q1: Does this sound right?

Q2: is it possible for me to use the wall thermostat in the house to effectively control the heat? how? How would I wire it?

The problem is, there's no on/off switch for a wood stove. If I stoke the fire, it will stay on and hot for hours. Assuming the blower in the wood stove blows while it is hot (I have a separate question on that), and the warmed air is going directly into the electric furnace, will the electric furnace now detect that there is warm air in its plenum, and turn on its blower?

In that case, should I expect the fan in the electric furnace to run more or less for the entire time the wood inside the stove is burning?

What's the appropriate way to modulate the heat, in this case? open a window?

2 Answers 2


Normally with this kind of setup, the wood stove would be considered your primary source of heat, not an auxiliary source. Its output is directed through your electric furnace just as a means of distributing the heat via your ductwork throughout the house. Based on your other question, the thermostat fan/limit switch ensures that as long as you've got a fire going, the fan will be running and distributing heat.

If you're not burning a fire, or it's really cold and your fire isn't keeping up, the furnace thermostat on the wall will tell the electric furnace to kick on and take up the slack.

Anyway to answer your specific questions:

Q1: Yes, this sounds reasonable.

Q2: Sort of. The wall thermostat will keep your house from getting too cold by turning on the electric furnace. There's nothing keeping your house from getting too hot, but then that's part of the charm of heating with a woodstove. You can always open a window (as you mention).

The furnace doesn't care what the temperature of the air in its plenum is, it will only turn on when the thermostat on your wall indicates the house is too cold. The thermostat on your stove, however, is measuring your stove's output air temp and if it feels warm air it will start blowing it. So expect it to be on for as long as you've got a fire burning. You could plug your stove thermostat into a switched outlet if you wanted some control over when the fan runs and when it doesn't.

  • 1
    Many thermostats have a "fan on/auto" switch which controls the fan - in "auto", they just run when the furnace is running, but in "on" they run all the time. You could switch it to "on" to effectively use the furnace's fan to distribute the heat from the wood stove.
    – gregmac
    Commented Dec 10, 2010 at 0:17

For modulating heat in a wood stove in general, you probably have air controls that should control the fire. You should be able to get some good coals going, put on a fresh log or two, and damp down the air flow considerably. Then it should burn relatively slowly, and not release so much heat.


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