Type of wall fan to move heat

[BC_Josh]

Hi. I'm looking to install a fan above my woodstove, into the wall.

I've already cut a hole in the wall, above the woodstove and I've found it has been good for circulating heat since the ceiling fan pushes it out of the hole into the cooler side of the house, and gets some of the heat out of my small living room. But, I'd like to do more, and I've been looking at some of the heavier-duty fans, used as exhaust fans (we see them in attics, or above cooking stoves and grills, used to ventilate kitchens in the backs of restaurants, or in some applications in greenhouses). Some of them are all the way up to 1/4 horsepower fans, the ones I've been looking at online (I'm assuming at top speed since they are speed adjustable), which is about 186 Watts of power. I notice most box fans that sit on floors are about 75 to 80 Watts of power and some of these wall through fans are similar wattage.

An example of a lower wattage model:

VEVOR Shutter Exhaust Fan, 14'' with Temperature Humidity Controller, EC-motor, 1513 CFM, 10-Speed Adjustable Wall Mount Attic Fan, Ventilation and Cooling for Greenhouses, Garages, Sheds, ETL Listed | VEVOR CA

VEVOR Shutter Exhaust Fan 14'' with Temperature Humidity Controller offers 1513 CFM airflow, 10 speeds, EC motor, and rust-proof design for ultimate ventilation.

www.vevor.ca

Does anyone have any experience with these kinds of fans VS the simpler wall-through exhaust fans that are generally used in small rooms like bathrooms?

I'm looking to get a lot of WOOSH to really suck out some of this heat out of my "sauna" living room, to better even out the heat differences between rooms, please and thank you.

Josh in the Selkirk Mountain Valley Range of BC
P.S. I have tried a lot of the fans on floors in the cooler rooms pointed at the stove, even cut a vent in the wall, next to the floor in a wee room off the living room, with a fan blowing cold air into the living room. These methods do work, but I've also found recently that my fan operating with downward air, isntead of pulling air up, seems to work better to disperse the heat. The fans on the floor method only goes so far when there is such a heat difference and the room with the stove is so small, time to suck some heat off!

 

[Murray01]

When my father-in-law built onto the existing cabin he used those 12” bathroom fans. He has them thermostatically controlled. The fans have a dial the allows us to set the fan speed. They work quite well, fairly quiet and easy to replace should they die. One thing about larger fans is they can make a room/hallway feel drafty, these little adjustable bathroom fans placed higher on the wall aren’t too bad for drafts.

 

[BC_Josh]

When my father-in-law built onto the existing cabin he used those 12” bathroom fans. He has them thermostatically controlled. The fans have a dial the allows us to set the fan speed. They work quite well, fairly quiet and easy to replace should they die. One thing about larger fans is they can make a room/hallway feel drafty, these little adjustable bathroom fans placed higher on the wall aren’t too bad for drafts.

I think some of the larger fans have variable speeds so you don't have to go too crazy with the drafts it might create.... but I don't know.

As of now, a little draft in the room would be welcome! It can get up to 83F (28C) in my living room after a hot fire on my catalytic stove which you have to fire hot initially to get a char on the wood, and be 70F (21C) in my diningroom/kitchen next to it. I'm currently opening the door for an hour or so every new wood firing which is kind of dumb too. It's annoying to say the least, and not healthy to constantly be going from an extreme hot room to a cooler room.

 

[BC_Josh]

Also, I wouldn't be getting a fan larger than 12 or 14 inches anyway.

 

[stoveliker]

I would be careful with a big fan sucking air out of the stove room. This could go sideways if the fan overcomes the draft (chimney suction) in the stove.

Instead, it works better to move cold air to the stove room. So rather than having a big fan up in the wall sucking hot air out, put a small fan low in the wall pushing colder air from the neighboring room towards the stove . Keep the doors open between stove room and that neighboring room and warm air will flow there to replace it.

This will create less "drafty feeling", creates no issues with stove leaking exhaust gases, and is less noisy - the fan only needs to run very low as long as it does so consistently. It'll create a loop current of air.

I do something similar though it's through the floor (basement stove). I suck cold air from my living room floor and deposit it on the basement floor. The warm air then gets pushed up the stairs to the living floor.
My fan is 25 W and you can barely hear it. (The system includes some ducting to go from the living room floor/ basement ceiling to the basement floor where the air gets deposited.)

 

[all night moe]

Exactly what stoveliker said.

It's much easier to move cool air. Trying to move warm air, the fan, tends to cool it off.

 

[salecker]

yes X3 on moving cold air instead of warm air

 

[dougstove]

Contrary opinion; I find moving hot air off the ceiling of the stove room works better than pushing cold air to the stove room. I ran a system both ways and had better results moving the hot air, contrary to advice here, and physics.
I had good products from: https://www.fantech.net/en-ca

 

[BC_Josh]

Contrary opinion; I find moving hot air off the ceiling of the stove room works better than pushing cold air to the stove room. I ran a system both ways and had better results moving the hot air, contrary to advice here, and physics.
I had good products from: https://www.fantech.net/en-ca

How did you move the air off the ceiling of the stove room? So far, I am finding success with having a box fan set up right near the doorway between the kitchen pushing colder air towards the stove. I notice the tissue test strip is waving at the same intensity as it was with having the box fan on top of the fridge, sucking warm air out of the room. There are so many factors involved.... it seems to just take experimentation, patience and perserverance to figure it all out.

 

[stoveliker]

I can't say what works in other places, but the key part of moving cold air is to move it slowly, so it doesn't mix with the warmer air. The persisting stratification helps make a convection loop that efficiently transports warm air. If you mix cold and warm, you're limited in how many BTUs you can transport.

That said, experiment heard their, so indeed you have to deal a lot of patient persistent trial and error.

 

[danrclem]

Does anybody make a small fan that blows in both directions? I had a window fan that would reverse but it would have been too big.

 

[highanddryinco]

the key part of moving cold air is to move it slowly

This.

 

[highanddryinco]

Different here but with similarities. My family room (stove room) is fairly large with a wide open ceiling that flows to the 2nd floor loft area. (aka, the hot area) Three bedrooms are accessed from the loft. Two bedrooms have walk-in closets at the absolute furthest point from the stove room and are also on the north wall of the house. (aka, the ice boxes)
A decade ago, I made a 6" square pass-thru between the two walk-in closets with the intention of mounting a square-housing computer fan in the hole, drawing the hot air into the Master bedroom, the master bath, and ultimately pushing what's left over to the walk-in closet for bedroom #2.
A decade later, the small fan I originally set on some books in front of the hole for a test...is still there, running on low-speed, and working beautifully with no felt draft. Drawing the hot air into the master heats it up very nicely. Bedroom #2 on the pressurized side, does warm up, but not near the amount on the draw side. The BTU's are mostly used up by the time the air reaches the fan.
Negative pressure is a beautiful thing.

 

[BC_Josh]

Drawing the hot air into the master heats it up very nicely. Bedroom #2 on the pressurized side, does warm up, but not near the amount on the draw side. The BTU's are mostly used up by the time the air reaches the fan.
Negative pressure is a beautiful thing.

Very interesting. Thanks for posting. I would imagine if heat is travelling up, it's got momentum and we can just kind of usher it along. Whereas, if the stove is very far away, down a floor, or around a corner, etc, we would need some kind of ducting to be able to shift enough cold air down to the floor where the woodstove sits.

Anyway, for me, it has worked well to cut an opening above the stove (14"x8" - between two studs) to bleed heat off it, with a ceiling fan in reverse, as well as a fan on the floor blowing colder air down low towards the stove. For the first time, the temperature on both sides of my one-level bungalow is always equal! Otherwise, one side was hot and the other was too cold and it's not nice, to me, going from a hot room to a cold one many times in one day, gives me the chills and sniffles.
So, I'm pleased as punch and very grateful to those who have advised on moving cold air towards the stove. Very counterintuitive, but works well. In the past, I had the box fan far from the door, and it didn't work; probably because a lot of the air would go into a side room as well, and the air had to travel around a corner to get to the stove.

My local computer repair shop has loads of computer fans they sell for cheap and can be easily wired up into whatever structure we build to house it. A nice option if we need it. However, I quite like just using portable fans with variable speeds. They are affordable and readily available in any hardware or department store, and can be easily moved around to experiment with different airflow scenarios.
Happy holidays to you all and thanks for the kind responses!

 

[sloeffle]

Had a few of these "back in the day" and they worked great.

Through the Wall 2-Speed with Airflow Adapter Room to Room Fan

 

[dougstove]

How did you move the air off the ceiling of the stove room? So far, I am finding success with having a box fan set up right near the doorway between the kitchen pushing colder air towards the stove. I notice the tissue test strip is waving at the same intensity as it was with having the box fan on top of the fridge, sucking warm air out of the room. There are so many factors involved.... it seems to just take experimentation, patience and perserverance to figure it all out.

Hi I had a long multi level ranch house with a basement under the central third. A big open room on slab had the stove; I put 6" stovepipe stack from near the ceiling, down and through a wall into the adjacent basement. I had a fantech fan with off/on/rheostat speed control that pushed the warm air through a duct to downstairs bedrooms. Passive air return was back through the house living area. It worked to keep stove room comfortable and the bedrooms warmer. I had earlier set up the ducting to run in the opposite direction, pulling cold air from the bedrooms to the stove room but it did not work. I since sold the house so no pictures.

 

[begreen]

This.

but the key part of moving cold air is to move it slowly, so it doesn't mix with the warmer air

And quietly. An industrial fan as shown is usually pretty noisy.

 

[BC_Josh]

Hi I had a long multi level ranch house with a basement under the central third. A big open room on slab had the stove; I put 6" stovepipe stack from near the ceiling, down and through a wall into the adjacent basement. I had a fantech fan with off/on/rheostat speed control that pushed the warm air through a duct to downstairs bedrooms. Passive air return was back through the house living area. It worked to keep stove room comfortable and the bedrooms warmer. I had earlier set up the ducting to run in the opposite direction, pulling cold air from the bedrooms to the stove room but it did not work. I since sold the house so no pictures.

Could you fill in a few details? I'm not sure I understand. I don't know what a "central third" means. The stove was in a basement room? And, your stovepipe venting system went from the ceiling of the stove room to adjacent basement rooms which were bedrooms?