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Outside Air Feed for Woodstove

 
Posts: 97
Location: Linneus, Me.
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Hello to all.  I need some advice regarding an outside air feed for my woodstove.  I live in an old northern Maine farmhouse that has a stone cellar.  I have an oil burner in this cellar and there is ductwork for the oil burner that goes to the rooms above.  I would like to know whether I can feed fresh air to my woodstove via a connection to a cold air return.  The woodstove is pretty much at one end of the house and I have a cold air return duct just a few inches away from the stove.  So it would be very easy for me to take air from this duct.  On the infrequent occasions when I would use the oil burner, I can simply shut the connection to the woodstove.  I would also hopefully be able to get the room that is far away from the woodstove a bit warmer.   Any reason why I should not do this?
 
Rocket Scientist
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Location: Upstate NY, zone 5
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A cold air return duct is trying to pull air into the furnace, so the pressure will be lower than ambient when operating. This is detrimental to feeding air to a wood stove. You should not rely on always operating it correctly for safety; you or especially someone else in the future will someday forget to switch things and cause a problem.
 
master pollinator
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Location: Canadian Prairies - Zone 3b
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I can see why you would want to do this. It might work, but I have concerns. Usually this sort of thing isn't done for safety reasons.

How do you propose to connect it? Higher end wood stoves usually have a connection for outside air. This is to provide external air for combustion so the stove doesn't pull in cold air through every crack in the house, potentially even affecting other combustion appliances with a negative draft.

Even with a tall chimney and a high end stove, the same negative draft can occasionally happen with certain wind conditions, with the stove struggling to maintain draft. This could potentially push combustion gases down into the ductwork. Not good.

If an insurance adjuster notices a physical connection between the wood stove and the ductwork, it's an easy excuse to deny a claim.

Personally I would add an efficient bathroom fan at the cold end of the house and push air through the cold air return to a vent beside the stove. I think that would be more effective.
 
Alden Banniettis
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Douglas, I like the idea of putting a fan at the cold air duct in the far room.  If I understood you correctly, I would simply place such a fan on the register-grate, facing down?  The route is about 45 feet long.
 
Douglas Alpenstock
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I guess you could experiment with a standard fan, but it may not last because the bearings/bushings aren't designed for that position.

An energy star bathroom fan will hold up much better and move more air. I would try to have a decent seal between the exhaust and the duct.

One other option is to set your forced air furnace to a "fan only" setting. Most of them have this option, or a switch may need to be added. I found this an effective way to circulate wood heat in the shoulder seasons -- early spring and late fall.
 
pollinator
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I am pretty sure I am not following. But that will NEVER stop me from blathering on....

I have an outside air feed to my woodstove. California made me do it cause I live in a modular home. Which is dumb because the house leaks air so bad there is no way my woodstove is going to asphixiate us. Anyways,,,

It is just a 4" dryer vent looking thing that fits up to the air intake on the stove and to a hole through the wall. I am actually considering putting a can fan inline to get that thing ripping in the winter when I feel like it could use some boost. Don't tell me anything, I have fire insurance!
 
Douglas Alpenstock
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Dan, the OP wanted to use the draw of the stove to move cold air from the other side of his house. In theory, this would circulate warm air to where he needs it.

Regarding outside air, if a stove has a connection for outside air, it's a good idea to connect it. The stove should run better and it'll be more efficient. Otherwise it would be sucking heated air from the house and blowing it up the flue.
 
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