Moving air thru the house

SWelsch

New Member
Dec 23, 2017
25
3
3
Maryland
I know my house it too big for my Acentra 52 insert but it's a secondary source of heat to my heat pumps here in Maryland. The pumps are efficient until we go below freezing. Below that and they need some help. Enter the Harman. I have a vaulted ceiling with a balcony open on both sides. It's typically 5+ degrees warmer up there than in the room with the stove. I just got a freestanding fan to push the heat back into the family room with the insert. Was wondering if I'd be better off sending the heat away from the stove, over the balcony back to the main floor to circulate better. Now that I've got you totally confused...thanks in advance for any thoughts.
Stay warm
 
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kjeremy2

New Member
Dec 27, 2017
21
2
3
New York
I personally use an oscillating fan too move it around the first floor and a corner fan in my stair way too send it upstairs. Hope that helps a little bit? Lol


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jackman

Feeling the Heat
Jan 15, 2013
477
129
303
Oregon
I learned it from an HVAC pro when he said, "you've got to move air." Any way you can is the way to do it. I use the heat pump fan and some small fans depending on the need.
 

SWelsch

New Member
Dec 23, 2017
25
3
3
Maryland
I personally use an oscillating fan too move it around the first floor and a corner fan in my stair way too send it upstairs. Hope that helps a little bit? Lol


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I assume the electrical cost of running a fan is minimal?
 

bogieb

Minister of Fire
Oct 31, 2014
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I would try moving the opposite way from the stove first, as you suggested. If you send it toward the stove you might possibly get it warm enough in there to shut down the stove while other parts of the house are cold.
 

Pelleting In NJ

Minister of Fire
Sep 26, 2011
528
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I use a large 12 inch Vornado fan, on top of my stove. They seem to move alot of air, seemingly further than some other fans I have tried.
 

aaronk25

Burning Hunk
Feb 15, 2017
162
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Rochester
It’s more about getting the cold air to the stove. Cold air can in some cases be easy to get there due to increased density. Just focus on moving the cold air to the stove room instead of getting the hot air away from the stove. The hot air will move by itself pretty well.


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drizler

Minister of Fire
Nov 20, 2005
998
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Chazy, NY 12921
I never had much luck with small ones. The best are those monster 16” that fit a window nicely. Big slow moving blades when on low move decent air quietly.and don’t create a huge draft. The trouble is those fans are bulky if in s hallway and not very nice looking wherever they are.
One thing I learned along the way is that fans pull air a lot better than pushing it for what that’s worth. That and really moving hot air with fans without noise or drafts is a lot like herding cats <>.
 
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maple1

Minister of Fire
Sep 15, 2011
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All else being equal, a fan will move more cold air than it will warm air, because cold air is more dense. So usually better to move cold air toward a stove than warm air away from it. I would also use a ceiling fan in a vaulted ceiling, blowing down.

What do you have for heat pumps? Every situation is different, but ours are way cheaper to run than it would be to burn pellets even at -15c and lower. Ours are new though, they have come a long way the past few years. I am now thinking about how best to circulate air between rooms in a couple of dead end loop cold spots that the heat pump air isn't quite reaching. A couple of through wall fans would do the trick, I think. Not fussy about cutting walls open & fishing wire, but results would likely be worth it. For now and a/c season.
 
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mudeprived

Burning Hunk
Oct 9, 2016
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It’s more about getting the cold air to the stove. Cold air can in some cases be easy to get there due to increased density. Just focus on moving the cold air to the stove room instead of getting the hot air away from the stove. The hot air will move by itself pretty well.


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This.


I started out trying to push the heat away from the stove but it is the fans drawing cold air to the store that works best.
 

jp99

Burning Hunk
Jan 7, 2015
140
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Ohio
All else being equal, a fan will move more cold air than it will warm air, because cold air is more dense. So usually better to move cold air toward a stove than warm air away from it.
You guys keep repeating this old wives’ tale. The density difference is only 3.2% from 68 to 86F and none of you will be able to tell the difference. And none of this reasoning accounts for the viscosity change in the air which affects your flow rate. You’re dealing with 3rd order effects, well below what you can sense.

We engineers in the electronics cooling industry never choose a fan location based on denser air. You can’t measure the difference even with our lab equipment. It’s not an important factor.

Choose the fan location that moves the air around with the fewest losses. That will maximize your air flow. In my hallway, that means moving hot air. The carpeted floor introduces far more frictional losses to the air stream that pushing air along the ceiling. If I had a tile or wood floor then the floor would likely be the better option.

Frictional losses are your concern.
 
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maple1

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The carpeted floor introduces far more frictional losses to the air stream that pushing air along the ceiling.

Until you come to a doorway.

Still remains that cold is denser - so just talking warm vs. cold, and the old all else being equal thing, it is still generally better to move the cold.
 
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drizler

Minister of Fire
Nov 20, 2005
998
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Chazy, NY 12921
The carpeted floor introduces far more frictional losses to the air stream that pushing air along the ceiling.

Until you come to a doorway.

Still remains that cold is denser - so just talking warm vs. cold, and the old all else being equal thing, it is still generally better to move the cold.
Yup those doorways rain all over your parade . My place like many has a nice bid deep transom 2’ deep from a vaulted ceiling to add to really trap the heat. It’s easy to see why pioneers lived in one big room. I tried one of those Doorway transom pie shaped fans once too . Sold that soon after, too loud and did very little even with a fan in the hallway trying to pull the cold back towards the stove. Nice draft though!

One place you really can move here and is upstairs. Too bad I got a ranch style which pretty much only is going to heat the kitchen in the living room. Like I said just like herding cats or sailing ,it’ll get there ......eventually.


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jp99

Burning Hunk
Jan 7, 2015
140
47
103
Ohio
The carpeted floor introduces far more frictional losses to the air stream that pushing air along the ceiling.

Until you come to a doorway.

Still remains that cold is denser - so just talking warm vs. cold, and the old all else being equal thing, it is still generally better to move the cold.
In my house, the data I took contradicts that. A fan on the floor didn't produce the same temperature rise in the bedroom that a fan on the other end of the hallway did pushing hot air.

All things are never equal. As I said, you're looking at minor effects vs major ones. Start with the major effects, take data, go with what works in your home. Just don't make blanket rules about minor effects. You can lead someone down the wrong path.
 
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rona

Minister of Fire
Apr 2, 2008
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southwestern Minn
You guys keep repeating this old wives’ tale. The density difference is only 3.2% from 68 to 86F and none of you will be able to tell the difference. And none of this reasoning accounts for the viscosity change in the air which affects your flow rate. You’re dealing with 3rd order effects, well below what you can sense.

We engineers in the electronics cooling industry never choose a fan location based on denser air. You can’t measure the difference even with our lab equipment. It’s not an important factor.

Choose the fan location that moves the air around with the fewest losses. That will maximize your air flow. In my hallway, that means moving hot air. The carpeted floor introduces far more frictional losses to the air stream that pushing air along the ceiling. If I had a tile or wood floor then the floor would likely be the better option.

Frictional losses are your concern.
One reason for moving the cold air towards the stove rather then blow hot air around is simple. During the summer you notice using a fan to blow hot air towards you cools you off. We don't need to be cooled off in the winter so forcing the cold air towards the stove lets the warmer air replace the cold without the fan moving it producing drafts
 

tadmaz

Member
Dec 21, 2017
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Erin, WI
I've tried pushing cold air towards the stove, didn't work. I blow against the face of the stove towards the hallway where I want to get heat. It works for me. Nothing else seemed to work, I tried many many different positions.
 

drizler

Minister of Fire
Nov 20, 2005
998
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Chazy, NY 12921
After screwing round with it for years I found the better answer is close off all the unused bedrooms and just let them cool off. The bedroom is down a 30’ hall around 2 corners so it’s almost next to but nowhere near the pellet stove. I just shut the stove way down to 60 at night and use a 1500 watt electric fireplace in the bedroom. It’s still cheaper by far than keeping the whole living room and kitchen 70 using a lot of pellets and trying to coax some of it around to the bedroom.
Honestly with the crazy price of pellets and oil tanking lately it’s cheaper to just use the boiler........


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Corey

Minister of Fire
Nov 19, 2005
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The density between cold air / warm air is so minimal over the temp differences we experience, I wouldn't even worry about it. It's like saying black cars go faster / get better mileage than white cars because the black surface is hotter, air is less dense, so black car is moving through thinner air than a white car.

The main thing in my experience seems to be that you want a thin stream of air moving along a surface... the ceiling, or floor. I used to prefer the ceiling, but found the fan left a dusty mark at it's outlet over the years, so now I move air across the floor and put up with the 'drafty' feeling when walking through the air stream... but the floor is much easier to clean than the ceiling.

What you don't want is a fan several feet off the floor or below the ceiling. This sort of tries to 'cram' air into a space and doesn't work as well as the slipstream of air at the floor or ceiling. Its sort of like turning a bottle completely upside down and having the water gurgle and splash out vs pouring it from the side and letting a smooth flow of water out and a smooth flow of air in.

I also had better luck shutting the ceiling fan off. While it does even out temps in the stove room, it disrupts the 'conveyor belt' effect of hot air out / cool air in.

Either way, experimentation is likely the key to the best set up for your case. Now that everything is dialed in, I found a small 6" / 12 volt box fan can move all the heat I need from the stove room to the bedrooms at the opposite end of the house.
 

UpStateNY

Feeling the Heat
May 4, 2008
368
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Catskill Mountains
It’s more about getting the cold air to the stove. Cold air can in some cases be easy to get there due to increased density. Just focus on moving the cold air to the stove room instead of getting the hot air away from the stove. The hot air will move by itself pretty well.
I agree. I move the cold air to the stove with floor fan in the hallway. Someday when I get central air conditioning installed, I will have the HVAC setup to move hot air above stove through attic ducks to the back bedrooms.
 
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