How Best to Move Warm Air From Insert to Bedroom Above?

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velvetfoot

Minister of Fire
Dec 5, 2005
10,006
Sand Lake, NY
If I put a couple of couple of vents in the floor over the insert, would the heated air flow into the room above and then through an open door back downstairs. There would be hot air coming up the stairs, I guess, but the upstairs never gets much heat now. I guess whichever the heat flow, it'd be good. Maybe a fan in the vent, but should it blow down or up? The insert would be right below the vent, but the fan is blowing air across the room to the stairs.

Another thing is that the bed is situated over where the proposed vents over the insert are.

Has anybody out there done this, or have any suggestions?

Thanks.
 

kiltedpiper98

New Member
Dec 22, 2011
26
North Carolina
Velvetfoot, I couldn't find it immediately, but I saw a post when looking for "moving air" (or moving heat or heat upstairs or heat to basement) I can across several threads with people talking specifically about through the floor vents. If I recall correctly people said that more than the heat going up, the cold air came down the vent, and the warm air moved up the stairwell (or another way) to the room above. I think it has something to do with the cold air being denser and more likely to move down, and something else about the thermal stratification in a room. There were also concerns about the free flow of air/fire in a fire situation where people where recommending fire dampers. You could try it with a small floor vent (if you don't mind cutting through the floor and ceiling) and see how it goes (a little risky). The gravity kits on the ZC FP we talked about in the other thread are designed to move the warm air up a floor. I understand that for short distances (and above the fireplace) these work fairly well. With you other question, after you install the vent, see if its hot air up, or cold air down. Then you could install the fan to boost the natural flow.
 

WoodpileOCD

Minister of Fire
Jan 19, 2011
722
Central NC
velvetfoot, I have done exactly that myself. I thought the warm air would rise into the bedroom but it was negligible at best. I now have a small fan laying across the vent in the bedroom blowing down and it is working like a champ. The cold air being sucked out of the bedroom creates a small neg pressure and is replaced by warm air going up the stairwell. I can stand on the stairs and FEEL the warm air rising up. Give it a try and let us know how it works for you. I'm thinking of building a small box that would cover the vent with a cutout for the fan rather than just laying it across the vent.
 

velvetfoot

Minister of Fire
Dec 5, 2005
10,006
Sand Lake, NY
Thanks. I'll do some more searching. I don't think I read about the gravity kit - I'll go back there now. I was poking around with the IR gun, and the air is definitely warmer on the living room ceiling rather than the upper area of the stairs, and the return air on the stairs was cool. Probably nothing a larger stove couldn't cure :) but I might for now be sticking with what I have. But you're right, there's no finish wood floor above, and the vents wouldn't be too obvious under the bed, if things don't work out.
 

begreen

Mooderator
Staff member
Nov 18, 2005
82,659
South Puget Sound, WA
Do you have a floorplan posted in another thread? I am wondering about the locations of the insert and stairwell relative to the room openings.
 
I posted a thread about Thruwall fans

https://www.hearth.com/econtent/index.php/forums/viewthread/82590/

which also has pictures of a passive (non-fan) vent that I built to allow faster migration of hot air from the livingroom to the upstairs rooms.



It works well for balancing the heat, though the response is slow when the house is cold. The key is to have a large area opening in the ceiling above the stove (mine is the maximum between the ceiling joists). This register is attached to a box above the ceiling which has two 8 in. ducts which are connected to registers in the upstairs rooms. I placed those registers as high as possible in the rooms to encourage the connvective flow. When the stove is hot, you can feel the air flow from the registers upstairs. Not as fast as a fan, but effective and much cheaper and quieter.
 

velvetfoot

Minister of Fire
Dec 5, 2005
10,006
Sand Lake, NY
BG: Sorry, no floor plan. It is a colonial with 1000 ft2 on each floor. The downstairs is open, with an open staircase in the middle. The insert is at a gable end.

Mr. Whoopee: Nice! I guess I could have a large grate like yours downstairs and two registers upstairs, on either side of the bed, using blocked off floor joists as a duct. Then, I guess there might have to be fans in both which might be noisy. Maybe if only one under the bed, not as noisy, but warm air would have to come out under the bed. I think we could get used to the ceiling grate. Maybe turn fans off at night. Probably won't be as agressive as far as ducting to farther rooms, but might try registers to draw cool air down. Of course, doors would have to be open for return air flow. Rheostat on fan probably needed. More thought needed, but nice to know it can work.
 

begreen

Mooderator
Staff member
Nov 18, 2005
82,659
South Puget Sound, WA
Still hard to visualize. Provide more info on the layout including room openings to the open staircase. Or scan in a simple floorplan. Somehow I am feeling that there is a simpler solution here based on the description.
 

begreen

Mooderator
Staff member
Nov 18, 2005
82,659
South Puget Sound, WA
MrWhoopee said:
I posted a thread about Thruwall fans

https://www.hearth.com/econtent/index.php/forums/viewthread/82590/

which also has pictures of a passive (non-fan) vent that I built to allow faster migration of hot air from the livingroom to the upstairs rooms.

It works well for balancing the heat, though the response is slow when the house is cold. The key is to have a large area opening in the ceiling above the stove (mine is the maximum between the ceiling joists). This register is attached to a box above the ceiling which has two 8 in. ducts which are connected to registers in the upstairs rooms. I placed those registers as high as possible in the rooms to encourage the connvective flow. When the stove is hot, you can feel the air flow from the registers upstairs. Not as fast as a fan, but effective and much cheaper and quieter.
Is this vent within 10 ft of the stove? If so, you should check code. It may be in violation. Is it at least fusible-link dampered?
 

begreen

Mooderator
Staff member
Nov 18, 2005
82,659
South Puget Sound, WA
I give up. Best of luck.
 

weatherguy

Minister of Fire
Feb 20, 2009
5,749
Central Mass
I have my insert in the fireplace downstairs with an open stairway leading upstairs, what I found is the cool air comes rushing down the stairway. I installed an 8 x 20 vent with a fire damper on the opposite end of the great room where the stairway is located. Now warm air gets pushed up through the vent and theres a noticeable difference in heat upstairs. I may put one in each of the bedrooms and see if that evens the heat out even more but so far Im happy with the way this one vent is working.
 

velvetfoot

Minister of Fire
Dec 5, 2005
10,006
Sand Lake, NY
3 sides are handrail, but the master br side is wall.
Not shown are two pocket doors for the master br.
 

weatherguy

Minister of Fire
Feb 20, 2009
5,749
Central Mass
velvetfoot said:
weatherguy, you put the 8x20 vent far away from the insert?
No, its near the stove, I meant away from the open stairway, I used a poor choice of words.
 

begreen

Mooderator
Staff member
Nov 18, 2005
82,659
South Puget Sound, WA
velvetfoot said:
My wildly inaccurate scrawlings:
No art critique here, they are very helpful. It looks like the place should heat pretty easily, including upstairs. My first thought is that the insert may be somewhat undersized for the job. But getting back to the heat circulation, here are a couple questions. What is the opening height near the stairway? Have you tried the fan trick?
 

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velvetfoot

Minister of Fire
Dec 5, 2005
10,006
Sand Lake, NY
The stairway opening goes right to the ceiling of the second floor, 16'.

Haven't tried a fan yet. Got a fan out and was going to put it somewhere yesterday, but needed extension cord, plus not sure if there's any room.

How about putting a ceiling fan over the staircase? Not sure which way to point the air direction however? That would mix up the stratified air flows, no? Is that good?

Of course, the insert is too small. I've been toying with the idea of ripping out the the insert and zc fireplace, tile, hearth, etc, but that's a pretty big step.
 

begreen

Mooderator
Staff member
Nov 18, 2005
82,659
South Puget Sound, WA
So the living room ceiling goes right from 8 ft to 16ft when it hits the stairway opening? That is, there is no enclosed support beam here?
 

pybyr

Minister of Fire
Jun 3, 2008
2,301
Adamant, VT 05640
velvetfoot said:
I have two recessed spots near the fireplace. Maybe something like this could work. Noise is key I suppose.
http://www.lampsplus.com/Products/Nutone-Recessed-Light-with-Fan__17645.html
Most bath-type fans are noisy as heck, not built for continuous duty (they won't last long if run a lot), and not electrically efficient if you are running them for substantial periods of time.

An exception are the Fantech in-line fans, which are close to silent, use relatvely little power in relation to amount of air moved, and can move a surprising amount of air through a 4 inch diameter duct or pipe.

I sourced some several years ago through a place called hvacquick.com

http://www.hvacquick.com/products/residential/Fans/Inline-Fans
 
BeGreen said:
MrWhoopee said:
I posted a thread about Thruwall fans

https://www.hearth.com/econtent/index.php/forums/viewthread/82590/

which also has pictures of a passive (non-fan) vent that I built to allow faster migration of hot air from the livingroom to the upstairs rooms.

It works well for balancing the heat, though the response is slow when the house is cold. The key is to have a large area opening in the ceiling above the stove (mine is the maximum between the ceiling joists). This register is attached to a box above the ceiling which has two 8 in. ducts which are connected to registers in the upstairs rooms. I placed those registers as high as possible in the rooms to encourage the connvective flow. When the stove is hot, you can feel the air flow from the registers upstairs. Not as fast as a fan, but effective and much cheaper and quieter.
Is this vent within 10 ft of the stove? If so, you should check code. It may be in violation. Is it at least fusible-link dampered?
Good question. As usual, building codes were the last thing on my mind. Yes, it is directly above the stove, no fusible-link, it's just an open duct system, much like the thru ceiling vents over the stove in my other home. Of course, that house was built in the '20s and the wood stove installed in the '80s. Others may want to consult their local building codes.
 

velvetfoot

Minister of Fire
Dec 5, 2005
10,006
Sand Lake, NY
I put in a radon 'system' using a 15 watt Fantech fan. It puts out considerable air, is quiet, and has been running for years. I'd use it for sure.
 
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