# new ductwork for wood stove



## MOgal (Jul 27, 2002)

We have a nice woodstove that will run us out of our remodeled former 2 car attached garage which is now a craft room/storage area. We have been thinking about using insulated flexible ductwork with an inline fan through the attic from the room with the wood heater in it to the main living areas of the house to better circulate the heated air. The fans we found at the local big box hardware store are from

http://www.suncourt.com/2Speed_Inductors.html.

Has anybody tried this and if so, what pitfalls did you encounter? Did you use a thermostat to control the fan or an on/off switch? What size duct and fan did you use? Where did you place the fan, some where along the ductwork or at either end of the ductwork? Most importantly, did it work to your expectations?

Moving the woodstove isn't an option. Besides we put the stove in that space because it was on the very end of the central air ductwork and stayed cold all the time--make that frigid because I've stored food out there that wouldn't go into the frig after holiday meals. I found a sawmill near us where I can get scraps, mostly oak, from pallet making to fuel the stove for little money. Good exercise and far cheaper than propane.

Thanks for your input.


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## Ed_Stanton (Dec 28, 2004)

I have one of these fans installed in one 6" metal duct tubes going from above my woodstove to pull air to another room about 15 feet along the ceiling. It moves air fairly well, but perhaps it's the metal duct tube, but the air coming out is not very warm, despite the basement and ceiling being warm. Also, the fan to me is too noisy, again perhaps due to the metal ducting, but I wouldn't think that it'd be much different with anything else.

I stopped using it and reverted back to gravity and cutting holes for air to move and putting register covers over the holes. This works for my situation to move air around the house. Woodstove basically in the center of the basement, with several ways for the air to move up and down through the house. I still have cool spots and warm spots and temperature differentials but overall it's better than living with the noisy fan that cooled off the air that it was moving.

Hopefully your situation is different and it works. Good luck.


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## MOgal (Jul 27, 2002)

Thanks, Ed. Our house is single story so we wouldn't have the advantages of the convection heat movement like you have. I think we are going to go with a larger diameter duct and since it must be insulated to go through the attic anyway, maybe we will get warm air in the living room. On that website, there was a sound muffler that we may have to get as well because DH plans to place the ductwork/fan over a doorway between the bedroom and the room with the woodstove in it. 

Thanks again.


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## greg273 (Aug 5, 2003)

I have my woodstove in a 10x10ft add-on room, and even with the door to the house open the air doesnt circulate well. ( it would be 100F in the woodstove room and 55F in the house...). So I cut a hole and put a fan in the adjoining wall, with both an on/off switch and a thermostat I took from an attic fan. Now, when the heat in the furnace room gets above a certain point, say 95F, the fan kicks on and starts blowing that warm air into the room. Pretty soon, the whole house is warm. And at night, when the fire gets lower, the thermostat will automatically shut the fan down.

This, plus a few strategically placed passive vents, circulates air to the entire house. 

HomeDepot or Lowes sells the thermostats, check in the attic ventilation area, they are less than $20.


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## tamsam (May 12, 2006)

I used a fan like that in an insulated flex pipe with great results. I used a heat register and made a cover for it to fasten the pipe to on each end. Just be sure you mount the fan to something solid. Sam


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## MOgal (Jul 27, 2002)

Thanks, Greg and Sam. We hadn't thought about a thermostat but it sounds like a good idea to prevent circulation of cold air as the stove cools down at night. Sam, what is the diameter of the fan and ductwork you used? We were thinking at least 8" for maximum air flow. DH had already thought about how to make a solid connection between the fan and the ceiling joists where he's going to tap into the electrical system. 

We had been thinking about pulling air from the warm room to the cold room through the attic but some other reading on line said that it's better to go the other direction. It made sense due to the cold air being denser and heavier pushing the warm air into the rest of the house. Also, why pull warm air through the cold attic even though it's in an insulated pipe? 

I surely do appreciate the input. DH won't be able to tackle this project for another 2-3 weeks but I'm getting excited about saving more money by not having to use so much propane. I'll report back about our results. Thanks again.


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## SolarGary (Sep 8, 2005)

greg273 said:


> I have my woodstove in a 10x10ft add-on room, and even with the door to the house open the air doesnt circulate well. ( it would be 100F in the woodstove room and 55F in the house...). So I cut a hole and put a fan in the adjoining wall, with both an on/off switch and a thermostat I took from an attic fan. Now, when the heat in the furnace room gets above a certain point, say 95F, the fan kicks on and starts blowing that warm air into the room. Pretty soon, the whole house is warm. And at night, when the fire gets lower, the thermostat will automatically shut the fan down.
> 
> This, plus a few strategically placed passive vents, circulates air to the entire house.
> 
> HomeDepot or Lowes sells the thermostats, check in the attic ventilation area, they are less than $20.


Hi Greg,
How big are the fan and the duct?

Gary


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## GREENCOUNTYPETE (Jul 25, 2006)

you may have better air movment if you use a squirl cage blower to feed the duct from the stove end.it volume and volocity is greater when pushing air than pull it in a duct 

you can probably push it right back into the duct you talk about inadiquatly suppling heat to that area.

you may also look into a majic heater a co-worker hooked duct work to one it took a little sheet metal work but it feed into his forced air furnace then he put a thermosatat on the blower in his furnace .to push the air he has a squirl cage blower pus cold ait into the back of the majic heater it gets heated and comes out the from turns a 90 and goes into the next room thru a wall were it is plumed into the cold air return.


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## OJ Rallye (Aug 4, 2005)

Hello Mogal,

I used a smaller fan in a 6" stove pipe. (I'm getting heat from an 8" tee that collects heat from around the 6" pipe from the waste oil heater.) The little fan couldn't push hardly any air through 30-40 feet of 6" stovepipe and the insulated tube. I moved it to the exit end and it works great. If you mount the fan at the source end, it has to push all that air.
If it is on the exit end, it only has to push a little and I guess the rest is drawn in easily.

BR
David


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## MOgal (Jul 27, 2002)

I'm so grateful for all this great input and I know it will save us some costly mistakes. Thank you all.

But if anybody else wants to chime in, feel free!


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## greg273 (Aug 5, 2003)

SolarGary said:


> Hi Greg,
> How big are the fan and the duct?
> 
> Gary


 It is an ~8" fan, I'll have to check, the amperage is around 1.5 or something like that. It is from an old kitchen exhaust fan. It is a bit loud, I would like to find something quieter and with less amperage. ( this is in an off grid situation, with limited PV power, especially in winter!)


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