Moving air with a fan

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chris5150

Burning Hunk
Nov 21, 2012
109
East Central WI
I have a fan in a hallway blowing cool air back to the stove room and normally run it on low. Does a decent job moving the warm air. Anyone have any experience with running the fan on medium or high working better than on low?

Thanks,

Chris
 
Last year I played with a fan blowing toward the stove. I didn't expect a whole lot as I don't have a problem generally speaking with heat distribution, but I wondered if it would make a difference. I found that it seemed I was able to get more heat in the house with the fan running than without. Enough so that I used it every night that it was particularly cold.

Running fan higher didn't seem to make much of a difference vs just having it running low. I don't have sufficient data to draw a strong conclusion, but my impression here (and your house certainly is different) was that just getting the cold air a boost toward the stove made most of the difference, rushing it past the stove had a very small marginal benefit over this.
 
I think it is best just to keep the air moving. The faster the air moves the more it cools. Which is why it is usually ineffective to run the furnace fan and move the air around...It just moves to fast. I run mine on low if needed. Usually just the ceiling fan running in reverse on low is enough to move air around my house.
 
The hallway I am trying to move the air down towards the bedrooms is about 20 ft.
 
My wood stove is in the living room. Our house is two story with the first floor being open and the second being a loft. The kitchen is always cooler on the first floor. I won't even start trying to fight that. However the loft is about 10 degrees warmer than living room. I have an exposed pipe all the way to vaulted ceiling. I turn the fans on up stairs to push the warm air down. I swear when I do my stove burns less wood and it helps all around.
 
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I use one of those Caframo fans on the floor to circulate the cooler air into the stove room, has a high and a low speed. The only difference I see from high to low speed is noise. I also have a small fan that screws into the top corner of the doorway leading out of the kitchen into the dining room, creating a circular air movement.
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For my situation I believe when I run the fan low, oscillating past kitchen, stove room and hall towards bedrooms, my home warms quicker than when fan is set to a higher setting.

I like low/oscillating.
 
chris5150 said:
Running the fan in reverse pulls the air up correct?
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Depends on what you deem "reverse" I guess. Lol. Like "turn the air up" when referring to AC, hotter or colder. That's an argument I still have with a couple of my friends
 
chris5150 said:
Running the fan in reverse pulls the air up correct?
Click to expand...

Normally a fan blows air on you, reverse is pulling air away from you. But then it depends on what side of the fan your standing on. Spiderman may say (as he hangs from my ceiling) that the fan is normal, I say it's reversed as I sit in my chair.

I think the basic principle is not try to move warm air to the cold area but move the cold air toward the warm.
 
I think that running the fan on medium or high is less worth it myself. At the end of the night when the fire burns down it then spends a lot of time moving really cold air than with a gentle breeze. While I'm awake etc. I run the fans on high (ceiling fan and thru-wall fan) but when I fill the stove up and shut it way down and go to bed I turn all the fans down nice and low for a slow and low distribution. I've woken up before with those fans sending cold air screaming through the house after being left on high all night and it wasn't much fun.

This of course is all dependent on the home, the amount of heat, firebox size etc. so your mileage may vary.
 
It is easier to move the cold air near the floor towards the stove for 2 reasons. First, it is denser than hot air (and therefore takes less velocity to push it). Secondly, by pushing the cold air to the hot region, you are simply accelerating the natural convection within your home.

There is a giant plume of hot air rising right around your stove to the ceiling and then curling outward. If you can assist the natural convection with low speed fans on the floor, you get the quickest response. Trying to blow hot air to other rooms will not work as well since it is not as dense and then possibly disrupt the natural convection currents.

Ceiling fans that blow upward assist with the natural convection in an individual room, and with large enough blades, can push enough hot air upward to create a flow of air. But a fan on the floor can be more efficient since it is easier to move the dense air.
 
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Both are effective in the right circumstances. Every house is unique so it pays to experiment to find the best combo for your house.

FWIW I find that a larger fan on low speed works the best at moving a large volume of air quietly.
 
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So if you are trying to move warm air out of one room down a hallway, maybe your best bet would be to not have a ceiling fan on in the stove room at all as the warmest air would be the air that would tend to move down the hallway with a fan at the end of it????
 
If the ceiling is high in the stove room as it frequently is, the ceiling fan helps break up heat stratification. Without it you could have a big hot blob of air at 100F sitting at the cathedral ceiling peak and the air temp at floor level only in the 70's. This is an example of why one needs to take air movement on a case by case basis. It depends on the house construction, room layout, ceiling height, stove location, partitions, insulation, etc..
 
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So, you would need to run a ceiling fan in reverse at a higher velocity to get similar results to a floor fan on low. Putting the floor fan to medium or high could increase the flow of air past the "speed of convection" (not sure if that is a real term). Or you would be pushing air faster than the air is coming to the fan. And then of course with a higher velocity convection current going (even with warm air moving past), things can feel cool. So, finding the right velocity and placement of floor and/or ceiling fans can be some trial and error.
 
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begreen said:
If the ceiling is high in the stove room as it frequently is, the ceiling fan helps break up heat stratification. Without it you could have a big hot blob of air at 100F sitting at the cathedral ceiling peak and the air temp at floor level only in the 70's. This is an example of why one needs to take air movement on a case by case basis. It depends on the house construction, room layout, ceiling height, stove location, partitions, insulation, etc..
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This is true, I have about a 20' ceiling in an A-frame house with the bedroom/bathroom being adjacent to the structure built with 7' ceilings. The A-frame part of the house with the loft eats a LOT of my wood heat. I plan on building a wall with a door for the upper loft area to secure some of my heat as that part of the house at this point is merely storage. I will be insulating the interior walls (weird I know) to keep my heat in the lower areas as best I can.
 
Timnus said:
So, you would need to run a ceiling fan in reverse at a higher velocity to get similar results to a floor fan on low. Putting the floor fan to medium or high could increase the flow of air past the "speed of convection" (not sure if that is a real term). Or you would be pushing air faster than the air is coming to the fan. And then of course with a higher velocity convection current going (even with warm air moving past), things can feel cool. So, finding the right velocity and placement of floor and/or ceiling fans can be some trial and error.
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Not necessarily. A ceiling fan moves a high volume of air due to its large blades. Volume is more important than velocity. Get too much velocity and the area feels breezy which cools down the skin.
 
begreen said:
If the ceiling is high in the stove room as it frequently is, the ceiling fan helps break up heat stratification. Without it you could have a big hot blob of air at 100F sitting at the cathedral ceiling peak and the air temp at floor level only in the 70's.
Click to expand...
I am confused--Some people are saying running in reverse pushes air up? --Wouldn't you run the fan the opposite direction than you would in the summer,? That is what I am doing now--leave it on medium low. You want to push the air down so it doesn't get trapped in the cathedral area but not cause a cooling breeze???
 
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Pulls the cold air up from the floor, heats it and circulates it throughout the house. It cuts down on the downdraft from a floor pushing ceiling fan pushing seemingly cold air down towards the occupants in the room. It's about heating the cold air, not moving the warm air which cools as it moves.
 
Like was said above...not every situation is the same. What is the same is that it is very hard to displace dense cold air with warm air. That is why folks move the cold air towards the warm thus creating a vacuum effect which the warm air flows into. All that probably goes out window when you have a 20' ceiling and your trying to pull cold air from the floor 20' away. I only have 8' ceilings and running my ceiling fan in reverse has enough of effect to raise the temps in the hallway by 2 degrees. Run your fan both ways and watch the thermostat and see what works best for you house.
 
I have 2 ceiling fans equal distance from the stove in the center of the room, closer to the wall, cathedral ceiling with 7'6" ceilings in the rest of the house (older rancher). I run one in forward and one in reverse on low, my theory is it creates a convection effect. I have a 10" circular fan in the next room pushing the cooler air into the stove room. Presently with a stack temp of 300ish it is 75* in the stove room and 65 in the dining room (where the pusher 10" fan is) and farther down the hallway where the bedrooms start its 64* and 69* in the kitchen which is "parallel" to the DR where the pusher fan is. This seems to work pretty well for me, I guess. Anyone see an issue with the ceiling fans running in opposite directions?
 
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dyerkutn said:
I am confused--Some people are saying running in reverse pushes air up? --Wouldn't you run the fan the opposite direction than you would in the summer,? That is what I am doing now--leave it on medium low. You want to push the air down so it doesn't get trapped in the cathedral area but not cause a cooling breeze???
Click to expand...

Pushing down is for summer when you want to feel a bit of breeze across your skin. That has a cooling effect as perspiration evaporates. In the winter you want to mix the air without feeling it. By blowing upward the hot air is forced to descend along the walls (the cold air source) and then be pulled back to the fan. This makes the room feel more uniformly warm without drafts. Click on this diagram to enlarge.

Ceiling-fans_h.jpg
 
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