In wall fan with thermostat to dump heat outside house?

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.

NBABUCKS1

Member
May 9, 2013
52
Wasatch Front, UT
Climate zone 7. Cold.


Wondering if there is a product on the market that will accomplish this. I'm planning on putting an oversized stove (morso squirrel) into a tiny house because frankly it's impossible to have a stove that is small enough for a 240 square foot place. We would sleep in the loft and here is the floor plan

p39vBfp.png

My plan would be to place a 2 or 3 inch fan in the wall cavity above the top window that would be attached to a thermostat to dump excess heat. Ideally PID controlled- faster spin when it's hot, slower when it's cooler. I figure with the loft being on the second level it's going to get hot in the first few hours of the burn

I'm sure the the response will be this place is too small for a wood stove and I agree with you but my heart is set on this. If you know of a better stove that puts out less heat with longer burn times I'm all ears.
 
Last edited:

stoveliker

Minister of Fire
Nov 17, 2019
1,955
Long Island NY

NBABUCKS1

Member
May 9, 2013
52
Wasatch Front, UT
the short burn time doesn't really seem fesable. I *think* I'd rather have longer burn and roast myself out vs super short burn that I have to reload every two hours.

Yes a pellet or propane stove would solve all this but i don't want that.
 

stoveliker

Minister of Fire
Nov 17, 2019
1,955
Long Island NY
the short burn time doesn't really seem fesable. I *think* I'd rather have longer burn and roast myself out vs super short burn that I have to reload every two hours.

Yes a pellet or propane stove would solve all this but i don't want that.

I hear you.
What about adding a heavy curtain in front of your loft. Open and close at will, but can keep some heat out of there?
 

tabner

Burning Hunk
Jan 17, 2019
207
Eastern CT
as to the larger question of pumping air out of the house, vs curtains, vs smaller stove, i can't really speak. But if you do end up going with a temperature activated duct fan, there are a bunch of good options. I just bought the AC infinity T8, it's on some 8" flexible duct (the ducting costs about $20), it has a temperature and humidity probe and you can set it to run on a timer, high/low temp, high/low humidity, etc. You can get them in 4" dia, 6" dia, or 8" dia. Lot of options on Amazon. I would just do some math with regard to CFMs and see what you need.
Only concern would be, if your duct fan is going to kick on and suck air out of the house, make sure you have an open window or something of that nature. These duct fans are going to create a pretty serious negative pressure in the house. Hopefully your stove will be on an OAK. But still, i'd be concerned about the duct fan kicking on and creating too much negative pressure if someone isn't nearby to crack a window.
1632324257909.png
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
26,137
central pa
Amazon product
do a search for camping wood stove. There are some small stoves designed for splits that are 6-12 inches long. That might work better they trying to keep a stove designed for a house from cooking you out.
Those are not legal to install in a home and are not built well enough to hold up when used as a regular heat source.
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
26,137
central pa
the short burn time doesn't really seem fesable. I *think* I'd rather have longer burn and roast myself out vs super short burn that I have to reload every two hours.

Yes a pellet or propane stove would solve all this but i don't want that.
Why not look at small catalytic stoves with really low turn down and long burn times. Pulling air out especially at the top of the house could very easily create negative pressure around the stove pulling smoke or carbon monoxide out of the stove into the home. It's a bad idea.
 

NBABUCKS1

Member
May 9, 2013
52
Wasatch Front, UT
Why not look at small catalytic stoves with really low turn down and long burn times. Pulling air out especially at the top of the house could very easily create negative pressure around the stove pulling smoke or carbon monoxide out of the stove into the home. It's a bad idea.

I actually looked into that and per the database there wasn't really any good options. Here is a thread I made looking for the lowest BTU options.

Cat stove Lowest BTU per EPA database

EDIT in looking at the EPA website I have found these:
- Woodstock 202 Palladin/204 Keystone - 7606
- Blaze King Ashford/chinook/sirocco - 8900
- Regency CI2700/HI500 - 8292


 

mightytitan9

New Member
Sep 18, 2021
29
Mound City KS
A bathroom exhaust fan or hood range fan should do all you need, just wire it to a thermostat and it will only come on when the thermostat tells it to.

So you wire it to a thermostat, it doesn't have power until it hits 80* (for example), at 80* the thermostat tells it to cool down. The exhaust runs until it cools it down and then the thermostat turns it off.

Another option is to simply sit there with a door or window open. We've had many of Christmases at my parents with the living door wide open :)
 

BKVP

Minister of Fire
Amazon product
do a search for camping wood stove. There are some small stoves designed for splits that are 6-12 inches long. That might work better they trying to keep a stove designed for a house from cooking you out.
Careful! Many "camping" models are not safety tested with published clearances.
 

BKVP

Minister of Fire
A bathroom exhaust fan or hood range fan should do all you need, just wire it to a thermostat and it will only come on when the thermostat tells it to.

So you wire it to a thermostat, it doesn't have power until it hits 80* (for example), at 80* the thermostat tells it to cool down. The exhaust runs until it cools it down and then the thermostat turns it off.

Another option is to simply sit there with a door or window open. We've had many of Christmases at my parents with the living door wide open :)
There are studies from Montana and other regions that show indoor air quality can be negatively impacted with cracked windows or doors..especially if they are near a wood heater/chimney system.
 

mightytitan9

New Member
Sep 18, 2021
29
Mound City KS
There are studies from Montana and other regions that show indoor air quality can be negatively impacted with cracked windows or doors..especially if they are near a wood heater/chimney system.
it's definitely possible, in my case it's a 25 foot chimney with a steady north wind and a door upwind from that. I'm not worried about any negative air quality from that.

Obviously properly venting the hot air outside is the way to go
 

Dataman

Minister of Fire
Sep 10, 2018
1,012
Newport, Wa
I would vote Electric or Pellet or Propane. or couple of grasshopper and have them chirp when you need heat. Wood will be hard to control without letting cold air in by Window or such. Besides Elec can be set into wall saving space in such a small house
 
  • Like
Reactions: BKVP