Routing wood-burning stove through living space w/exhaust heat exchanger (e.g., Magic Heat)

iconoclasthero

I've been thinking about the following setup:
On the ground floor, install a residential interior wood burning stove (of a type to be determined). The intended routing of the exhaust stack will be through the ceiling into the corner of an occupied 2nd-floor bedroom, through the unfinished attic, and then through the roof.

As the stack passes through the 2nd-floor bedroom, I'd like to install an exhaust-gas heat exchanger, e.g., the Magic Heat device.

Without even considering the issue of exhaust draft if the heat exchanger is used, is such a setup even possible or is this a literal pipe dream?

LS123

hello @iconoclasthero ... what you are trying to do sounds wonderful and would be nice to get the best out of the heat of the wood stove. I have also had the idea slimier to that..
Below are what I have learned...
1) this all depends on the heat output capacity of the wood stove. (some wood stoves with catalyst could produce exhaust gas temp closer to 700 F. Depending on where you live, all new wood stoves sold must have certain level of specification to reduce exhaust emissions ... for example in CT all new must meet certain specs.
2) Depending on the stove you may have to either have 6 inch or 8 inch double wall steal pipes.
3) Wood stove install must be done with a permit from your town, city, and the person must have valid license and insurance.
4) Exhaust pipe must least amount of horizontal pipes and more vertical pipes.

Depending on where you live, you probably can get a free consultation and estimate from a certified seller / dealer of wood stoves... there are so many good brands such as regency, summit,etc. I do not think you will be able to get anyone to come to your house and get an estimate from HD, Lowes, Ace etc.

License pro will be able to tell you what you like to do is doable and meets building codes etc.

Best!

Jamie Hall

And be sure to burn only dry, well-seasoned hardwood, and get that chimney -- especially above the heat exchanger -- swept regularly. Creosote will build up above the heat exchanger, and a chimney fire can be very exciting...

hot_rod

The main issue is cooling the exhaust gasses too much and you can cause the flue gas to condense and form creosote quickly. I wold want a temperature gauge above it to monitor the temperatures.
A CO detector is good to have in a home with wood burners.

EdTheHeaterMan

You also need to consider maintenance. How easy will it be to remove the connecting pipe and remove the "Magic Heat" heat exchanger (HX)? The creosote, ash, and soot that will accumulate on the exhaust side of the HX will need regular maintenance. Your standard chimney sweep will not work with that HX box in the way. I might suggest a "maintenance section of pipe" that can be installed whenever the chimney needs to be swept. They make telescoping sections of that pipe.

That pipe must be rated as Class "A" vent pipe. This pipe is rated for up to 2200° or 2400° The more readily available "B" vent is not approved for solid fuel appliances. B-vent is only approved for Gas burning appliances.

Make the duct connections (if any) and wiring with some kind of quick connect device so you can take the HX outside for maintenance. I would not want that ash and soot in my bedroom.

STEVEusaPA

You're asking for trouble.

LS123

I dont know what region you live at, in CT you must get a permit, most new wood stoves require double insulated pipes inside the house, building inspector must sigh off o it before you use... make sure you meet building code, install by a certified pro for fire insurance reasons...

perhaps you can have an opening on the floor assuming wood stove is one floor below.

My neighbor has his wood stove in the basement, he has cut open small holes on first and second floor with covers on them... they look like what people put on forced air covers... I dont know what they are called... may be grills

wood stoves produce good amount of heat that rise quickly... you save all the extra work when heat exchanger require @EdTheHeaterMan mentioned... probably not worth all the extra work

Jon_blaney

I am a wood stove user. Do what LS123 suggested.

Jamie Hall

Or not so small holes. At one point in the dim past I lived in a house (ca. 1780 -- think a bank barn for the layout) -- in Vermont, as it happens -- which was heated -- all of it -- by a pot-belly Glenwood parlor stove in the walkout basement. The main floor had a nice big grate above the stove and a return grate at the opposite end of the house. Then there was another grate which led up to the bedrooms under the eaves; that returned down the stairs. My recollection is that the grates were about 2 feet square.

But you need enough grate area -- and you need a return grate at least as big to make it work.

LS123

@Jamie Hall I agree... my neighbor has few rectangle about three corners so close to the wall, I think each one is no more than 12 inches by 12, then he has a decorative lid on them... he has them supported by metal bars or something like that and arrange furniture etc so nobody would put their foot thru.. he has them first floor, he has them second floor the same... he runs the stove almost always and house is pretty comfortably warm. He seldom gets oil, perhaps once or twice max during the winter season.

JUGHNE

The floor/ceiling grates that were common in wood burning houses were about 14 x 16. Designed to fit between 16 OC floor joists. The floor one was heavy enough to walk on and had a damper to close as wanted. The stairwell door was often the return air path.

LS123

@JUGHNE thanks for this info....

Bob Harper

Can't do it. You can only penetrate walls and ceilings with listed chimney-- not stovepipe. Class A chimney listed to UL 103HT is insulated. Also, where it passes through living spaces or in attics where people could conceivably come in contact with it, it must be protected by walls or bulkheads that meet the 2" clearance to combustibles.
Those Magic Heat gimmicks from the 70's caused a lot of chimney fires because they cooled the stack too much gunking it up with creosote. Nope, bad idea. A woodstove is a radiant heater. If you need heat on the second floor, install a stove there. You'll need listed stove board protection for the floor and walls. You can use listed close clearance double walled stove pipe to get within 6" of combustibles walls. Otherwise, 18" clearance.
Sorry, you're having a pipe dream.

psb75

"Magic Heat" is a heat exchanger in the main exhaust vent of a wood burning appliance--and just "bad news". It's also a chimney sweep's 'nightmare.' It is too much of a restriction for unburned flue gasses. There is ALWAYS the potential for burning fuel with improper moisture content. Get a really good wood stove, properly sized and installed properly to local code and put in floor grates above as described by others. Allow for proper return convection using grates or stairwell.

EdTheHeaterMan

Sometimes reinventing the wheel is fun, Sometimes it can be a disaster. The Magic heat is a good idea, but only a good idea if you provide for the problems it will create. People have been heating with wood stoves long before gas and oil heaters were available. Look at all the success stories from that old technology and learn from the mistakes. Does the good idea part of the equation outweigh the problems you will encounter? Will you be able to maintain the integrity of the system?

After you are gone, will the ones you left behind be able to easily do the needed maintenance? If that even matters... Everyone's situation is different.

Yours Truly,
Mr.Ed

HomerJSmith

There ain't no such thing as a free lunch. Consider this carefully.

PC7060

This reminds me of the heat savers that went on dryer vent which redirected dryer exhaust providing "heat and moisture" (lots & lots of moisture) into house. The lint built up quickly or leaked all over creating big fire risk.

I see you can still buy on Amazon as "Deflecto Extra Heat Dryer Saver"

Love the warning provided: "Do not vent gas clothes dryers into bathrooms or bedrooms; Some building codes may restrict the use of this product, always check the local codes in your area"

EdTheHeaterMan

Yea that’s what I’m gonna do. Call the Building Inspector and ask him if I can do something stupid. 

I’m sure he will say “sure go ahead and vent that clothes dryer into your basement and get lint all over your furnace or boiler combustion air intake 

here is the fire chief’s direct line if you need it next month.”