Add on wood stove in garage

[Jakereardon96]

Hello I'm new to this site. Sorry if this is not in the correct forum.
I'm looking to install a afd on wood/coal stove in my garage to heat my house. I do not have a basement and have no place in my house to place it. I got it cleared by insurance to install in my garage. The question I have will I have issues heating my house with this method. I will run the duct under my craw space with insulated ductwork . Will the warm air cool off too much like this. It will be appox 25' away from my central furnace .Also. How would I go about hooking into my furnace. Could I direct the heat into the cold air return of my furnace?
Thanks in advance

 

[kennyp2339]

That's going to be very difficult, your trying to join (2) loops into one instead of one series loop on the returns. Typically the air coming off of the wood furnace is about 110 - 115 deg f, anything less will just feel ambient / drafty chill when trying to heat to 70-74deg. Now couple that with a run of 25ft main trunk before reaching the central heating location and the addition of the 2nd return air (cool air) on the main furnace (acts like a vacuum) further cooling the hot air produced by the furnace.
Second tough thing is the constant maintenance for changing dirty air filters from the furnace return, unless your garage is super clean, and the added draft coming in from the garage doors to create make up air, since your sending the garage air through the duct work, and feeding the fire with it.

 

[bholler]

That's going to be very difficult, your trying to join (2) loops into one instead of one series loop on the returns. Typically the air coming off of the wood furnace is about 110 - 115 deg f, anything less will just feel ambient / drafty chill when trying to heat to 70-74deg. Now couple that with a run of 25ft main trunk before reaching the central heating location and the addition of the 2nd return air (cool air) on the main furnace (acts like a vacuum) further cooling the hot air produced by the furnace.
Second tough thing is the constant maintenance for changing dirty air filters from the furnace return, unless your garage is super clean, and the added draft coming in from the garage doors to create make up air, since your sending the garage air through the duct work, and feeding the fire with it.

His wood furnace would need to be hooked to the cold air return. You cant pull air from the garage for that.

 

[begreen]

This may need rethinking and consultation with the furnace mfgs. Wood furnaces are not made in a down flow configuration and it sounds like the garage is on the opposite side of the plenum. What would happen to duct temps coming off the furnace in the event of a power outage? If permitted, clearances would need to take this into account.

Perhaps building a bumpout from the house for an EPA ZC fireplace or alcove for a freestanding stove would work better?

 

[Bad LP]

Why not a wood boiler and use a HX in the current furnace. A 25 foot run of pipe is nothing.

 

[DoubleB]

Surprised you got the insurance company to agree. In fact, I wouldn't trust that answer. You spend money and time to install, then once they see it they back out. You ask the manufacturer and they don't endorse a garage install, at least because there is no gravity flow in a power outage as @begreen said. You look for a different insurance company and can't find one. No homeowners insurance and have fun with your mortgage lender.

I'm not saying all those would happen, but I'd spend some extra time thinking through your options.

(P.S., is your garage below your house, to at least address the gravity flow during power outage?)

 

[begreen]

Why not a wood boiler and use a HX in the current furnace. A 25 foot run of pipe is nothing.

Is there a small, reliable wood boiler that would do this? What would be required for storage and safety in the event of a power outage?

Note that many local ordinances do not permit a wood burning appliance in a garage. Some do but with stipulations like it has to be 18" off the floor. It's best to run preliminary ideas and plans by the local inspecting authority before proceeding.

 

[Highbeam]

Wood boilers are extremely expensive compared to wood furnaces and wood stoves. Since the op has no basement or room for the furnace inside we might assume a pretty small home which makes wood boilers harder to justify.

Hard to imagine a home that couldn’t make space for a woodstove.

 

[maple1]

I'm not sure on the OPs plans here. Referred to a stove, not a furnace. Could be a sort of jimmied up affair involving a stove, and separate duct work just to move air from close to the stove, into the house? Or could be a simple mix up of terms.

Going down with ductwork off a furnace isn't a good idea. Would almost certainly require a power-off damper at the top that would open up to allow convection flow to dump heat into the garage if the power goes out. We haven't been given many details here but if insurance has seemingly OK'd something without getting into a discussion about those kinds of things - I wouldn't trust that 'OK' too far. Or there might be some fine print that passes liability on to the person/persons who professionally installed & certified it. In which case, if it wasn't professionally installed & certified you would be up the creek without a ladder...

 

[E Yoder]

I may not be understanding everything- but normally sending air from a garage to the house is a big no-no? The air would need to be ducted in and out.
A wood boiler with a heat exchanger in the duct would solve a lot of issues along with heating dhw. At a cost of course.

 

[maple1]

I may not be understanding everything- but normally sending air from a garage to the house is a big no-no? The air would need to be ducted in and out.
A wood boiler with a heat exchanger in the duct would solve a lot of issues along with heating dhw. At a cost of course.

Yes, we're a little short on details. The garage air & house air should remain separate - via a closed duct system. I have a feeling the insurance person might have been a little short on details also - but I could certainly stand to be corrected.