Moving cold air through home to

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crh704

New Member
Mar 19, 2012
13
Central CT
I have been considering buying a wood stove for some time now and finally pulled the trigger on the fireplace xtrodinair elite 33 last week (figures it is going to hit 80 in CT this week!). Anyways, I did get a few days of usage before the warmup and noticed that I was able to get my living room (vaulted ceiling) up to the high 70s but my other rooms didn't warm much at all. The wood stove is at an extreme end of my house. Rather than using box fans I was thinking about cutting a floor register in a room on the opposite side of the house (same floor) as well as next to the wood stove. I would then connect the two and install an inline duct fan blowing the cold air from the far room into the stove room.

I do have a ceiling fan running in the living room

Question - would this create negative pressure in the cold room and positive pressure in the stove room? Would that help the movement of warm air through the living spaces between the rooms?

Anyways, loving the stove! Thanks for any thoughts/responses!
 
That sounds like an ok plan if the duct is insulated and if the passage to the far area is always open. I would do a test with a simple table or box fan first to prove it will work for this situation. Place it on the floor at the far area pointing toward the elite and see how it works out.
 
Any way that you can exchange warm and cold air from one part of the house to the other is going to help even temps out throughout the house, providing, as BeGreen said, that the ducting is within the insulated envelope of the house.
I run the fan on low on my HVAC and it does the same thing, however there are some homes (I am told) who's heating ducts run through un-insulated areas in their attic. As you can imagine, when they try to move air though these un-insulated ducts the air is cooled and the heat loss is so great that it just doesn't work for them.
Of course you'll never get the far end of your house the same temp as your stove room by simple air exchange. The best you can do is moderate the temps so it's not as warm in the stove room and not as cool in the far rooms.
 
Good call on the test. Ill try that first to see how that works before breaking out the saw......booooo (wife is probably secretly happy).

Carbon, does the hvac impact your stove performance?
 
I have found that all we really need is a small fan pointed towards the stove room. It makes a world of difference ! In the rooms with ceiling fans if any I would recommend that you set them to suck air up so it will push the cold air down the walls following the natural air flow. It sounds crazy but works well as cold air flows down the walls naturally anyhow. That combination may be all you need to do.

Good luck
Pete
 
Carbon, does the hvac impact your stove performance?
Not sure how running the HVAC fan could directly effect my stove performance??? But perhaps I'm not understanding your question.
Running the hvac fan just helps to circulate the air in the house. Even with the fan on low every few hours all the rooms have all the air replaced, so all the warm air in the stove room ends up getting circulated through all the other rooms in the house, that can't help but warm them. Not to mention the relatively cooler air also helps cool the warm air in the stove room thus moderating the heat in there too. A common problem with wood stoves is the rooms where they are located can often get uncomfortably warm.
 
I was thinking a similar plan, but a bit different. The local Lowe's sells round insulated ducting, my thought was to poke a hole in the ceiling above the stove and run the duct(s) from there to the back rooms through the attic. Duct fans controlled by thermostats in the rooms they serve. Louvered vents in the bedroom doors near floor level so the cold air can escape and move down the hallway back to the room with the stove.
 
Basically that is how i have mine set up I use a bath room 50 cfs. then I ran to 3 inch duct in unfinished basement far end of house to a 3 inch T to another bath fan by stove on snap disk or manual front or rear or both fans switched. works good on the wood stove and the replacement gas stove with no oppositional fans.I have no ciealing fans.If I dont use the fan or fans I get about 12 inches of cold air at floor level feet get cold

View attachment 63694
 
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Note that code requires a return duct to be a minimum of 10 ft away from the stove or fireplace.
 
Carbon - I was thinking that depending on your hvac intake placement it may make it more difficult for the stove to draw air? I read a few other posts and it sounded like that was an issue for some..... I'll give it a go

SOunds like others have had success with the inline duct fans so its good to know that option would be worth while as well. I'm still getting comfortable with the stove and how hot it can get without going nuclear.....prob won't get a handle on that until next year since its going to be in the 80s this week!
 
Carbon - I was thinking that depending on your hvac intake placement it may make it more difficult for the stove to draw air? I read a few other posts and it sounded like that was an issue for some..... I'll give it a go

SOunds like others have had success with the inline duct fans so its good to know that option would be worth while as well. I'm still getting comfortable with the stove and how hot it can get without going nuclear.....prob won't get a handle on that until next year since its going to be in the 80s this week!
I think you'd have to have whole house cold air return within a foot or so of the stove intake to have any siginficant "vacuum" effect on stove performance. However, there is a safety issue should the stove draft somehow reverse and start venting carbondioxide into the house. This could, and does, occasionaly happen under a specific set of circumstances. If the return air vent happen to be located very close to the stove if this happened it could suck and fill the whole house with carbondioxide very quickly. I think this is the main reason for the 10 ft clearance code begreen mentioned.

On the subject of duct fans, I also utilize a duct fan to suck the warm air out of the top of my stove room. It is basically only a through the wall fan and it's a bit loud, so we tend to only use it at night while we sleep. or while we are away, but this one really helps draw the hot air out of our high ceilings in the stove room and boost it towards the stairwell which then naturally flows upstairs.
Our house has mostly 8 ft ceilings, but the stove room has 10 ft ceilings, so without this duct fan booster a lot of hot air gets trapped up in that extra 2 ft area near the ceiling.
He's a diagram of air flow.
DuctFan.JPG
 
A quick and simple way is to use a box window fan. Blow cold air at floor level into stove area through doorway. The warm air them comes out over the top of the fan.
This worksgreat on a single level house. On your multi level complicated layout this may not work.
A fan is about $20 and moves a lot of air. It is a good way to test your idea if you layout allows it.
Actually we use this method permanently. The fan is just offset so you can walk by it. Very little power compared to our big heatpump blower. Even on the low setting it circulates well.
 
A quick and simple way is to use a box window fan. Blow cold air at floor level into stove area through doorway. Very little power compared to our big heatpump blower.
Are you sure about that? How many watts does your heatpump blower on low use compared to your window fan? And how many CFM do they blow respectively?
 
Window fan on medium setting = 65 Watts
Heatpump blower, only, no compressor = 300 Watts

The heating system has to blow through a restricted path of tubes, not large hall ways and open doorways. Also the blower has to push air through a very restricted heating coil tighter than a car radiator.

The heat pump blower has to develope ( use lots of power) a good pressure to go through the restrictive path.
A window fan uses all of it's energy to develope large flow but no pressure.
Also notice heating and air conditioning systems use blowers and not fans. Fans are not good at pressure fpr restricted paths.

Do a rough measurement of your air ducts and they will probably equal the area of the window fan. Now put your face, the area of a vent, 3 feet away from the fan. Then put your face 3 feet away from the heating duct vent. I bet the window fan is a good wind on your face but the heating duct is just a gental breeze.
 
Window fan on medium setting = 65 Watts
Heatpump blower, only, no compressor = 300 Watts

The heating system has to blow through a restricted path of tubes, not large hall ways and open doorways. Also the blower has to push air through a very restricted heating coil tighter than a car radiator.

The heat pump blower has to develope ( use lots of power) a good pressure to go through the restrictive path.
A window fan uses all of it's energy to develope large flow but no pressure.
Also notice heating and air conditioning systems use blowers and not fans. Fans are not good at pressure fpr restricted paths.

Do a rough measurement of your air ducts and they will probably equal the area of the window fan. Now put your face, the area of a vent, 3 feet away from the fan. Then put your face 3 feet away from the heating duct vent. I bet the window fan is a good wind on your face but the heating duct is just a gental breeze.
Steve do you not have a low setting on your heatpump blower? 300 watts is obviously your high setting, and not really nessesary for just circulating the air. I can't confirm, but I'm pretty sure the low setting on mine system is under 100 watts.

It is true you'll likely lose some air volume do to the restriction of the ducts, and if all your intested in doing is move air from one room to another adjoining room, then a window type fan would win hands down in that sort of application. However if your wood stove is located at one end of a sprawling house, and you want to move air throughout the whole house (not just from one room to the next), then a HVAC blower is going to work better. To prove that case, set your window fan in your doorway at one side of your house and go back 10 feet and feel the wind in your face. Now go into the farthest room in your house and feel for a breeze. Nothing right? With my HVAC blower I can go into any room in the house and still feel a positive air flow through the registers, which tells me that all the air is getting positive air circulation thoughout the whole house.
IMHO if you have a small, one level home a small portable fan in a doorway would probably work best, but for larger multi level homes your'll likely get better results with using your HVAC circulating the air thoughout the whole house, after all that's what it's designed for. That of course is assuming that's what you want. Some people close off rooms in their house and are happy to heat just a few of the main centrally located rooms to conserve the heat, in that case it would probably be better to use a portable fan again.
 
We have a long ranch style house. 2 heatpumps. One at each end. Ducts not connected.
One is a 30 year old Bard. The other is a 25 year old Bard. Both have blowers with only 2 settings, On and Off :>)
The older one has one motor with double ended shaft. Inside blower on one end and outside coil fan on the other.
It actually takes more than 300 watts just to move the inside air because it is also running the outside fan.
The 300 Watts I mentioned is only for the newer HP that has a separate inside air blower.

Also the 30 year old one has a standby compressor heater that draws 300 Watts, always on.
We can run a small room heater on the low setting for 8 hours and still use less power than the standby mode uses in a day. We usually just turn the breaker off on that one. It is in the lesser used end of the house.
They are roof mount "Over and Under" types. Not easily converted to newer systems with remote compressors.
Anyway, for us, using a box fan to move wood stove heat is much better updating to 2 new heatpumps at about $6,000 each, installed.
Another interesting note;
The box window fan has a big difference between low and medium speed air flow but very little difference in power.
So on the lowest setting out of 3, it may be much less efficient.
 
I like "pulling from cold room"
Per KWh, I believe a hassock fan captures more air to move than box fans, a few feet from a door, throwing cold air out of space, warm-air flies back along ceilings and some overhead obstructs.
Too:
Little 40-watt ducted 6" fans reduced to 4" (standard sheet-metal piece coupling) handles a 20x20 or larger air rotation in 28 ft high vaulted areas.
"Vertical Air Stabilization" of VASCO units in JC Penny in the 80's (saved 23% Heating, 17% Cooling), and today a spin off of the JET AIR 50 (Bede Nat'l) of the 90's,--- hassock fans upside down and sideways are throwing air over 60-ft NO DUCTING REQUIRED like the Honey Well turbo blaster adjustable...
but see if motor bearing(s) can tolerate vertical upside down, etc, positions in vaulted areas..

RADIANT FLOOR HEATING TYPICALLY LEAVES 8-12-DEG AIR FLOATING WARMER AGAINST CEILINGS THAN ROOM AIR AT KNEES:
I LIKE OTHER'S- SOME AIR ROTATION. (REDUCES MOLD IN BASEMENTS/ CHECK RADON GASSES AND SEAL RETURN-AIR DUCTING CLOSE TO 98%, TAPE FURNACE CABINET WITH ELECTRICAL TAPING AT ALL SEAM-DOOR-CRACKS-FRAMING.

VERTICAL AIR ROTATION DONE:
Tennis courts (Inside) to small offices on fan controls and fan in drop ceiling above egg-crate panel even works well.

If high register is used
FOR discharging (supply) air,
think of water-hose-nozzle "button" that water wraps around at a 'focus' to allow STREAMING fluid flows (we played with! Hah!)
At register fins:
1 or 2 pair inner vanes bent outward ~ 5deg outward,
and the res 3-deg inward, and experiment and find standard ceiling HVAC registers can be re-bent-adj if adjustable to throw air as well as all the "new" computer-designed EXPENSIVE registers ! - only - 6 bucks= 40-ft sideways air throw capable,
and over 35ft vertically downward.
Air usually leaving at a standard 500 fpm (push 600 fpm) velocities leaving registers...
even 300 ft/min velocity works significantly. One 4x10 can turn over air in rooms like a 'pond-bubbler' in a pond, in over 500 sq ft , 6-8ft away from walls (leave wall air-films to 'insulate' for other gains ).

geopros.org
 
I have been considering buying a wood stove for some time now and finally pulled the trigger on the fireplace xtrodinair elite 33 last week (figures it is going to hit 80 in CT this week!). Anyways, I did get a few days of usage before the warmup and noticed that I was able to get my living room (vaulted ceiling) up to the high 70s but my other rooms didn't warm much at all. The wood stove is at an extreme end of my house. Rather than using box fans I was thinking about cutting a floor register in a room on the opposite side of the house (same floor) as well as next to the wood stove. I would then connect the two and install an inline duct fan blowing the cold air from the far room into the stove room.

I do have a ceiling fan running in the living room

Question - would this create negative pressure in the cold room and positive pressure in the stove room? Would that help the movement of warm air through the living spaces between the rooms?

Anyways, loving the stove! Thanks for any thoughts/responses!

How much do you think that stuff would cost anyways?
 
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