# Wood Stove heat to cold air return?



## canuck7870 (Dec 4, 2008)

I have a 900 sq ft bungalow, and am going to get an efficient wood stove put into the basement.   I'm also getting a high efficiency gas forced air furnace to replace the old one in the utility room next door.  There is a length of cold-air and a length of warm-air ductwork running along the ceiling across from where the wood stove will be.  My question is:  Can I somehow get that warm ceiling air from the wood stove into the ductwork, to have it circulated around the house?  Like a couple of one-way dampers, then run the furnace fan to circulate it?  Any experiences?

Mike


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## Hanko (Dec 4, 2008)

if you had a very slow speed on the furnace it might help, but I think the wind chill effect that moving air creates might offset any benifit


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## oconnor (Dec 4, 2008)

Fellow Canuck

I assume by the reno you are doing, you have looked into the Energuide for Houses programme?  There is some great info in the site for the programme about how to get the most out of these two installs. Also, I recommend the Residential Guide to Wood Heating (link in my signature) as a read before you head into the stove install.

As for using the furnace fan to move hot air from the stove - BE CAREFUL! I filled my bungalow with smoke doing just that because I reversed the flow in my exterior chimney.  If you think in terms of getting cold air from upstairs into the room where the stove is, you will be better off.  Even just adding warm air outlets from the furnace to the room where the stove is, and circulating the air with the furnace fan without the furnace burner running can be a much better idea.  If the cold air side of the furnace system is set up well there will be duct losses and electricity to run the fan, but less risk, and it can work well. Try to avoid pulling any air out of the room where the stove is (even consider a grate that would allow you to close a cold air return in the stove room)

The hot air will rise all on its own - what will keep parts of the bungalow cold is the air that the hot air "traps", because the cold air has no where to escape to.  In my bungalow, I ran a dedicated cold air return system to service the 3 bedrooms and hallway directly above the rec room where my stove was. It pulled the air from these rooms and returned it to a register near the floor in the rec room.  This helped avoid stack effect, avoided stratification in the rec room (cold air from upstairs was still warmer than cold air on the floor in the rec room), and was controlled by a thermostatic switch that ran the fan when the rec room temp exceeded a set limit, so it would shut down once the stove burnt out.

Moving hot air is likely to get you into trouble with both code issues and the laws of physics, particularly in a basement istall, and especially if you have an external flue.  Moving cold air back to the stove is a better plan.


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## LLigetfa (Dec 4, 2008)

oconnor said:
			
		

> Moving hot air is likely to get you into trouble with both code issues and the laws of physics...


I've sometimes skirted code issues but have yet to be able to defy the laws of physics.

Rigging dampers that short circuit the cold returns is bound to have a detrimental effect on furnace operations.


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## canuck7870 (Dec 5, 2008)

Thanks for the replys and links to more info.  I need to do some reading apparently.


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## searay220 (Dec 5, 2008)

I have a small cape cod style home with a Regency wood insert that works great. The only problem I am having is getting the heat to the areas of the house furthest away from the stove. My thought is somehow to circulate the warmth through the cold air return which is in the same room as the stove. How if at all possible run the furnace blower without running the furnace. I have the forced hot air sytem and there should be some way to utilize the heat duct for heat transfer to all the rooms in the house. Any thoughts or ideas about this. Thanks ahead of time.


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## oconnor (Dec 5, 2008)

There should be a switch on the furnace controls (not necessarily on the thermostat) that you can push in and will start the blower.

That said, please pay attention to how I worded the post above - moving hot air is hard.  Think in terms of moving cold air, and you will have better luck.  Give the forums a search for move cold air, and start reading, and you will see a trend in opinions - moving cold air is a better plan.

How to move air around in the house is certainly an item that gets discussed alot here, and the answer is always the same - move the cold air back to the stove.


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## Dustin (Dec 5, 2008)

I have attempted it, many times and it never worked. You loose a ton of heat in your ducts. There is just not enough heat from the stove, to keep the ducts warm enough.


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## searay220 (Dec 5, 2008)

Wow I thought my idea was a good one. I stand corrected. Thanks. So to move cold air to the stove what do you do a couple of small fans on low placed in the cold areas? By way this site is great. Lots of stuff here.


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## canuck7870 (Dec 8, 2008)

OK.  Thanks for all the advice again.  Now for another option: My father-in-law tells a story about his dad having a stove in the basement, and cutting holes in the ceiling, putting in grates, and letting the heat rise through.  Any opinions or experiences on that?

I should be doing a search on this, but how about a wood "furnace" that could be coupled with my new gas furnace?

(BTW, the new gas furnace will have a DC motor, so running it all the time shouldn't cost too much)


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## oconnor (Dec 8, 2008)

Lots of storeys about the basement stove and cutting holes - aside from the safety issues in the event of a house fire, it works.  When my father-in-law was a boy, thier "furnace" was a barrel stove built into a concrete block box, with hot air ducts on top, and passive cold returns to the bottom.  Worked quite well, that is, until the house burned down.  Good thing they had all that lumber cut for a new barn, or it would have been a cold winter.

They were able to reuse the foundation though.


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## bull (Dec 8, 2008)

i have had a squirl cage fan made into some duct that i got from a job and was going to use it to push the hot air through my duct system until i read  that it insant a good ideal . my house is a split level and of coarse stove in the basement. could i go to the otherside of the house where it stays colder cut a hole in the floor and run it under the house, cut another in basement wall and push the cold air back to the basement . to draw the heat toward the colder area. have been fighting this problem for years. please advise , if this will work.


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## oconnor (Dec 9, 2008)

That is essentially what I did in my bungalow - but - you might want to experiment with a fan first.  Just put it in the cold room, on the floor, and point it to where you want the cold air to go. See what results you can get.  It will be way easier than cutting and running ducts.

If you opt for the duct idea, be aware of fire safety issues when you cut thru floors and walls - these are firestops, and in an actual fire, holes cut thru can comprimise the precious time you will have to get out.


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## vasten (Dec 9, 2008)

One trick that I thought was cool that is not mentioned in here, is to just place a cold air return over the stove in the ceiling, and have it linked to the furnace normally.  Dont try to "short circut" anything, then when the furnace kicks on it is drawing warm air from above the woodstove into the heat exchanger of the furnace to be reheated and sent back out into the house.  The idea here is you are taking 70-80 degree heat and raising it to 80+ degrees Vs.  room temp 65-68 degree heat.  

You are not "pulling" heat from the woodstove but letting it work in conjunction with the furnace to make both more effecient.

But why not consider a wood furnace then?  Comparable in price and even heat through out the house, ties into all of your exsisting duct work?


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## webbie (Dec 9, 2008)

There are code and safety issues involved.....AND also the fact that most such installations do not end up working good.

Think about it - a return duct is a very strong suction.....and you are putting it near a stove that needs to pull air from the room and send it up the chimney. The result could be the duct making the stove backdraft and then the smoke or smell spreading through the house.

Also, since the furnace is engineered to put 120,000 BTO or so into the air moving through it, the tiny amount of air coming in a room return slightly warmed (say 5,000 BTU) will be "lost in the sauce" so to speak!

My suggestion - don't do it.

Use small fans...room to room fans, even a kitchen or ceiling bathroom fan. Or, just let the stove do the job it was designed to do...and get a central heat wood burner if you want to go that way. Sometimes an attempt to go just a bit too far.....ends up going too far.


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## webbie (Dec 9, 2008)

I threw a quick wiki article together with some suggestions and links:
https://www.hearth.com/econtent/index.php/wiki/Move_Stove_Heat_around_house/


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## bren582 (Dec 9, 2008)

I tried it as I thought I had a perfect setup for this sort of thing.

I have a variable air speed handler that allows running the fan at 40percent "Fan Only" mode. even at this slow speed any heat in the air drawn into the main return on the ceiling in the fireplace room was lost in the vents and I guess from wind chill affect. The air at the fireplace room ceiling level is 75-80DegF, When I measured the air temp coming out of the vents in other rooms the temp was right back down to 65DegF so I essentially lost most if not all the heat affect from the insert.

The experts on this site suggest pushing cold air low and slow to the floor towards the stove, feeding that cold air to the blower and forcing more warm are out of the room into the rest of the house. 

I have found this method to be most effective and I can tell you I hate being wrong about just about anything or being told what works best by folks that clearly know better than I.. 

Your mileage may vary depending on your setup.. Worth a try but the success rate seems low..  Would love to hear if anyone has had success with it and how..


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## Cearbhaill (Dec 9, 2008)

My insert is in a basement with an unfinished ceiling- all my furnace ductwork is exposed.
I did have a cold air return installed in the basement (distance from insert *is *within code, and it's drafty enough that negative pressure isn't a problem), but as the furnace never runs I never use it. I could do fan only I suppose, but I don't like the noise of the air handler.

I have considered just detatching one of the air ducts from the existing hole in the floor, then setting a fan over the register upstairs to push cold air down. As my furnace never runs the ducts are unused, the hole is already there, and it seems a simple enough operation.

What am I overlooking?


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