Moving heat around with fans

Xtrl9

New Member
Jan 14, 2016
94
Va
In the past I have moved the hot air coming off a stove around the house by sucking it into the back of a fan on low and moving it upstairs, now that I have an insert in the main floor I want to keep some heat on that floor and move it upstairs too.

If you want to move more air you just end up cooling it down right? What if you just move a lot of cold air (fan on high) towards the stove so it can mix with the hot air there and eventually you will end up with overall higher ambient temperature right?

I am looking at getting a ceiling fan for the room with my insert in it but don't want to push all the hot air back down as my bedroom is up the open staircase from the stove. A lot of people on here have referenced moving air with fans and I've read some interesting thoughts both about sucking the hot air or blowing cold air. So I wanted to make a thread where you lay down your knowledge about fans. I am prepared to be blown away. Or provide pictures if my layout could cause basic blowing techniques to be ineffective.

Here is a rough floor plan. The blue pen indicates where my master bedroom is upstairs. I only drew the floor i was trying to heat. There is a fan box already mounted in the living room. Its directly centered in the living room between the blue hashed line and on the ridge board. 20170201_005004.jpg 1485928696347192302853.jpg

And there is the perspective from the front door
 
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Dix

Minister of Fire
May 27, 2008
6,315
Long Island, NY
Need layout.

I've played with ceiling fans, box fans, etc. Got my house down, lol !!
 

yooper08

Minister of Fire
Jan 4, 2016
618
South Lyon, MI
Ceiling fans work well when they're running in reverse as they distribute stratified hot air at the ceiling back down the walls.

Otherwise you generally have better results moving the cold air rather than hot air. You end up getting a convection current going.

Personally, I have a little Vornado fan at the bottom of my basement steps pointed towards the basement insert. Walking down the steps once the current is established, you definitely know when your face has it the warm part.
 

Xtrl9

New Member
Jan 14, 2016
94
Va
I played with having a fan in the hall to blow cold air out of the back of the house and also moved it to the right of the front door. So far it seems that by the door got more heat upstairs. Woke up to 70 degrees up there monday with no help from the heat pump. What else do you need to see?
 

revdocjim

Burning Hunk
Sep 7, 2015
189
Japan
Our cabin has a bedroom on the first floor, off the kitchen and it gets no heat whatsoever. I ended up spending a few nights there in late fall and the first couple nights I was really cold, even with the door open 24/7. So then I put hearth.com knowledge into practice, placing a fan on the floor in the doorway, blowing cold air out of the room. The next morning the room was much warmer than it had ever been before. The cold air got blown out at floor level and warm air flowed into the room above the fan. Worked like a charm! Cold, dense and heavy air is much easier to move than warm air.
 

yooper08

Minister of Fire
Jan 4, 2016
618
South Lyon, MI
I don't have any evidence to back up my theory, but the density of air at 80F vs 60F is right around a 1% (or less even) difference, very negligible. My theory of why we find it easier to move the colder air is not because it's actually more dense, it's the fact that its less turbulent than the hot air above it. Meaning, the cold air is more likely to move in straight lines vs the hot air above that's moving faster and potentially in various directions as it spreads out and cools.

Edit: to add a little more to this in regards to the cold air, its much more stable in temperature therefore its easier to move in straight lines with a fan. Stable temperatures equates to more stable air, which is easier to move about is the basis for my theory.
 
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jeff_t

Minister of Fire
Sep 14, 2008
4,202
SE MI
My theory is that cold air at floor level has fewer obstructions to negotiate, i.e. doorways and headers. The warm air replacing it doesn't have any choice in the matter. It's going to move.

I found that taping strips of TP at the tops of doorways makes it easy to see if you're moving good air when you're trying to figure out fan placement.
 
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jetsam

Minister of Fire
Dec 12, 2015
4,720
Long Island, NY
youtu.be
I found that taping strips of TP at the tops of doorways makes it easy to see if you're moving good air when you're trying to figure out fan placement.
Wife: Explain this to me again.

Me: It's the traditional wood burning ceremonial trappings of my people!

Wife: Now explain why you used duct tape instead of painter's tape on the mouldings.

Me: Don't oppress my native traditions! *runs away crying*
 
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Woody Stover

Minister of Fire
Dec 25, 2010
12,160
Southern IN
now that I have an insert in the main floor I want to keep some heat on that floor and move it upstairs too.
Is there a vaulted ceiling in the stove room, or just a smallish opening at the top of the stairs to your bedroom? Tell us where the heat is going now, vs. where you need the heat to go. Is too much warm air going upstairs? Are there kids that hang out in the other BRs on the main floor, and they need heat?
We let our bedroom get cooler, we just open the door from the stove room a little to keep it from getting too cold in the BR.
 

Dobish

Minister of Fire
Oct 26, 2015
1,993
Golden CO
i will have to post a picture of my layout and see what y'all would do.... moving heat around my house is terrible!
 

jeff_t

Minister of Fire
Sep 14, 2008
4,202
SE MI
I've also found that a ceiling fan in reverse can make a sort of a wall of air that won't let warm air out of the stove room.

Moving air is all about trial and error.
 

revdocjim

Burning Hunk
Sep 7, 2015
189
Japan
I've also found that a ceiling fan in reverse can make a sort of a wall of air that won't let warm air out of the stove room.

Moving air is all about trial and error.
Which direction do you mean by "reverse". Blowing up or blowing down?
 

revdocjim

Burning Hunk
Sep 7, 2015
189
Japan
Blowing up.
I was always told that upwards was the winter setting and downwards was the summer setting, which is a bit counter-intuitive and I observe that lots of people do it the other way around. I'm still not sure which is most effective.
 

Xtrl9

New Member
Jan 14, 2016
94
Va
Is there a vaulted ceiling in the stove room, or just a smallish opening at the top of the stairs to your bedroom? Tell us where the heat is going now, vs. where you need the heat to go. Is too much warm air going upstairs? Are there kids that hang out in the other BRs on the main floor, and they need heat?
We let our bedroom get cooler, we just open the door from the stove room a little to keep it from getting too cold in the BR.
Vaulted all the way up, probably 20'. Actually right now its just me in the house upstairs, had a renter in one of the bedrooms but he's moved out. so I've been keeping the door to the basement and both bedrooms closed to keep the heat to myself! In the process of selecting another renter but don't want to literally invite trouble into my house. The spare rooms are easily 10 degrees different with the insert going and was curious about how I could keep it warm back there and upstairs in my room. The other thing I should mention is I have my HVAC fan circulate air for 15 mins every hour to try to even it out. good/bad/depends on return?

I was always told that upwards was the winter setting and downwards was the summer setting, which is a bit counter-intuitive and I observe that lots of people do it the other way around. I'm still not sure which is most effective.
See this is why I started a thread.
 

Xtrl9

New Member
Jan 14, 2016
94
Va
I've also found that a ceiling fan in reverse can make a sort of a wall of air that won't let warm air out of the stove room.

Moving air is all about trial and error.
Life is trial enough man, I'm trying to reduce my error by drawing on more experienced house warmers. :) This was kind of my concern with a fan in the living room with the insert, I still want a portion of that warm air to come into my bedroom.
 

jeff_t

Minister of Fire
Sep 14, 2008
4,202
SE MI
I was always told that upwards was the winter setting and downwards was the summer setting, which is a bit counter-intuitive and I observe that lots of people do it the other way around. I'm still not sure which is most effective.
I don't use them much in the winter, and have them blowing up in summer. If it's on, it's because I want to feel some air circulating, and I don't normally sit in the middle of a room.
 

Dmitry

Minister of Fire
Oct 4, 2014
848
CT

Dobish

Minister of Fire
Oct 26, 2015
1,993
Golden CO
definitely clockwise in the winter....
BPB-FanDirection-Illo.jpg

when you are standing under a fan moving counterclockwise, you can feel the draft. Very rarely you will feel the warm air blowing down on you. We notice a 4-5º difference when the fireplace is going and the fan is moving slowly in reverse.
 

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tpenny67

New Member
Dec 17, 2016
82
New England
My ceiling fan only blows down, though being 10+ feet off the floor I haven't had much chance to inspect it closely to see if there's a direction switch somewhere. On the lowest setting you don't really feel the draft once the air is warm. It does seem to do an okay job of pushing warm air down against the cold floor, and also moving air along the floor towards the stove. It does that last part so well that I measured the floor at 120* on the upwind side and 150* on the downwind side with my IR thermometer. 150 degrees is uncomfortably hot on bare feet. Next week I get a new stove that should heat the air instead of the floor and walls :)
 

JotulOwner

Feeling the Heat
Oct 29, 2007
354
Long Island, New York
With the exception of a mostly decorative stove top fan, I never move the warm air from the stove room with fans. If I really want to move warm air to the second floor, I slightly open a window in the stove room. The cold air entering displaces the warmer air and forces it upward. Yes, cold air entering the house can be a problem if your stove isn't producing enough heat, but I haven't had that problem.