Anyone install ductwork with a blower to bring heat into distant room?

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Hubjeep

Hubjeep

Member
Jan 3, 2008
87
Long Island, NY
The 20'X22' room with the wood stove has a 12' ceiling and makes up half of the house. There is an open hallway to the rest of the house (8' ceiling), but the furthest bedroom is around a corner.

I was thinking about installing a duct at the peak of the 12' ceiling and running ductwork through the attic into the far bed room with an inline blower fan like this one. to help bring some warm air and circulate it back through the hallway. http://www.smarthome.com/3012.html

I have no idea what diameter I would need or CFM blower. The one I posted above is 8", anyone install such a set-up?

Here is a MS paint drawing not to scale.
stoveduct.jpg


Thanks,
John
 
8" should be ok, you might also experiment with taking the cooler air from the back room and blowing it to the stove room. That may pull the warmer air back to the back room.
I will be doing something similar. But I am going through a closet. Keeping the inline duct fan accessible in case I want to reverse it in the warm seasons. And the run is 3'
remember, a longer run means the air will cool while traveling through the duct. Thats why I say experiment. And you may find that blowing the cool air into the stove room, pulls the warmer air to the rear room. Use fuse linked registers for fire spread protection.

There are also 2 speed models available. On the lower priced ones DO NOT use a dimmer switch to control the speed. The ones where you can use those type switches are expensive.
 
Before you go to the hassle, take a desk or box fan and put it just outside of the bathroom. Point it towards the living room and set it on low. Let us know how that works out.
 
Do some searches in the archives as well. Do you have a basement? I would be inclined to install in line blower extracting cold air at floor level from said bedroom and discharging it in to the stove room. This duct work could be run under the floor. Seems like general wisdom on the forum to heat hard areas is to move the cold out of them. Warm air would then naturally fill that vacancy. You could experiment first by laying flexible ductwork from said bed room down the hall to the stove room on the carpet. Find a small fan that fits the duct or jury rig it to be efficient. You are trying to suck the cold off of the floor similar to what a furnace cold air return does. Good luck. Either way let us know what happens.
 
I am considering a similar setup for the distant bedroom. Keep us posted of your findings. It would probably help to wrap the duct with insulation to keep the heat in.
 
I second the box fan at floor level. If you're really wanting to get heat to the back bedroom try closing the doors to the bath and other bedroom when you set up the fan.

Doing a similar thing makes a big difference in my house.
 

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I don't know if you already have ductwork in the attic, but could the warmth have some unintended effects, like ice dams?
 
Thanks for the replies,
There is no basement, house is on a slab, and there is no ductwork in the attic.

I am concerned that the warm air may just stay at the top of the taller ceiling instead of migrate to the other rooms if I try pulling the cold air out of the bed room.

I suppose the fan could just be installed 180* out to either bring air in or out, in either case both will have to be mounted at ceiling height since there is really no other way to situate them.

-John
 
I think the 500 cfm is overkill. I have one of those 75 cfm doorway fans (a good one - very quiet) and it can move a ton of heat out of the room my stove is in, albeit I am moving it up some stairs.

One of the main considerations is that houses usually have a sort of natural circulation pattern - and it is better to work with it than against it. If you can figure out what that is, you are better off. I tried to figure mine out -ended up using incense to figure where the air hit first. It was quite enlightening.

I would do a smaller vent - like 3 or 4" and make sure you insulate it.
 
I just did this this past weekend, but to three bedrooms.

The red is the stove, and all grey areas vaulted ceilings; the green the ductwork and the blue the in-line fan. I was experiencing 10 degree differences between the living/dining/kitchen and the bedrooms. Additionally, the bed rooms wouldn't begin to warm at all untill the living room was 80f. I reasoned that all of the heat was being trapped up infront of the stairwell, and once down the hallway (14ft) would immediately begin to rise up since the ceilings there are high aswell, requireing alot of heat to make it down to "living" space. The little corner fan I installed at the hall entrance was working, but not enough. So I began to dream...

Up to the double T (I bought 2 split them and joined the halves) is 8". Beyond it 6", I figured I needed the reduction to "stall" the air enough to get it to all three rooms. I was worried that 8" all around would result in all the air being moved only in a straight line. As I was installing it, I discovered that the fan wasn't even necessary, each register hole I cut I was immediately followed by being washed over by warm air (w/o ductwork!). I bought everything at Home Depot including the fan. I used flexible insulated ductwork (I'm considering "upgrading" to rigid if I can figure out how to get it in that space without removing the entire hall ceiling). I cut a large hole in the hall ceiling to do all the work and get the large peices in.

Result: 5-7 degree difference (why I'm considering the "upgrade"). I really hate doing patchwork (I used a panel to cover the hole in the ceiling) but I think I'm going to have to bite the bullet and make a large hole above the stair well to install rigid duct work.
 

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ixDragons-
Nice, that looks very similar to what I plan on doing.

Why install rigid duct over flex tube? The flex is so much easier to work with. Also, what size vent (register?) did you use?

Thanks,
John
 
Hubjeep said:
ixDragons-
Nice, that looks very similar to what I plan on doing.

Why install rigid duct over flex tube? The flex is so much easier to work with. Also, what size vent (register?) did you use?

Thanks,
John
Click to expand...

Thanks! The flex was very easy to work with, but I'm a perfectionist (why I hate patching drywall). I figure the rigid will have less turbulence allowing for easier/faster air flow. I'm not sure if it's enough to make a difference. I haven't made up my mind yet though, I only considered it because I have to patch one wall where I cut the register too low. Since I'm patching anyway...

Infront of the stairwell is 14x8 and the bed rooms is 12x6
 
JUst rip the drywall down in that hallway ceiling, run the duct & put nice pine tongue & groove back up in its place. ;)
No taping, spackling or painting. Just stain or clear coat and done. ;). You could even go ever the old drywall just shim where the cut out sections are.
 
Jimbob said:
Yep, I used an inline fan like this one. Works well.
Click to expand...
Ahhh, You got the expensive one. Made much better than the home cheapo ones.
 
I installed an inline fan with flex ducting in my last house. I believe I used a fantech fan approx 275 cfm's and I was able to raise the three upstairs bedrooms by 10 degrees in the dead of winter. This was in a poorly insulated house. I chose flex for the ease of installation. took approx less than 2hrs to run the duct put in a register run the elec. and mount the fan. I too was moving hot air didn't think to try cold air at the time. All in all it did what I wanted it to.
 
Moose said:
I installed an inline fan with flex ducting in my last house. I believe I used a fantech fan approx 275 cfm's and I was able to raise the three upstairs bedrooms by 10 degrees in the dead of winter. This was in a poorly insulated house. I chose flex for the ease of installation. took approx less than 2hrs to run the duct put in a register run the elec. and mount the fan. I too was moving hot air didn't think to try cold air at the time. All in all it did what I wanted it to.
Click to expand...

This is exactly what I did also. My input register is almost directly above my Napoleon 1900 stove. The air temperature there is 110 degrees. I run 30 feet of flexible 12" conduit and loose 18 degrees. Net gain in temperature was 10 degrees in the far master bedroom where the exit register is located.

Since this master bedroom had a walk in shower/bath with literally no door and effectivly part of the master bedroom, I put my exit register above the shower stall. This dries it out, keeping mildew away and the tiles warm to the feet.

My fan is an 8" 275 cfm model I bought at Freidman brothers for about $40.
 
Very interesting post. I want to warm up our living room. There is no even semi direct pathway from my heater to our living room. 10 degrees would be great. I can heat up my office with our Rinnai to about 80, maybe 90 (never really tried because it was too hot...but with the air being sucked to another room I can probably just put it on full blast), not 110 F though. I am going to try using existing duct work with a fantech inline fan to pipe air into this room. These vents and registers are in the ceiling, and there is one register directly above the heater and one directly above our couch in the living room. I didn't want to be disappointed by air flow so got the most powerful fantech 6" fan. It's about 150 watts or 483 CFM @ 0" (not sure what this means in reality). I could just not believe that a 30 watt fan was going to do anything useful. Hopefully this does what we need. If it does, I may consider hooking up another fan to our bedroom on a thermostat via a "Y". Where do you put the fan? I was told half way between the source and destination. BTW the fantech tech support was great. They responded to my questions within hours.
 
If you do run duct work from the stove room to the back bedroom, you will probably have better running the inline fan in the opposite direction of what you had planned. Pull the denser colder air from the bedroom and blow it into the stove room. This will create air current from the stove room back down the hallway and into the bedroom to make up for it.

The topic of moving heat has come up a few times. Move the cold air in order to displace the warm air to where you want it.

-SF
 
For me I am using cheap insulated flex duct. Right now I am blowing from the room with the heater at full blast to the cold living room and the temp has gone up from maybe 64 to 66 but I am not seeing much more than 66. I've had it going for about an hour. It is not even cold outside today. This fan is definitely powerful too. The blowing action is much much more than my central air blower. So I guess I will try reversing it in another hour or so. Not sure how long I should expect it to take for temps to change. Again I do not have a stove, just a direct vent gas heater so my source temperatures are MUCH lower.
 
I did something like that..I put a induct 8" fan in the wall up near the ceiling and attached a elbow on the end so i could direct the heat where i wanted it..it works great!!
 
I've got almost the exact layout as yours (stove location, vaulted ceilings, etc.), except my bedrooms are all on the first floor. Any recommendations on how to approach this with everything on one level?


ixDragons said:
I just did this this past weekend, but to three bedrooms.

The red is the stove, and all grey areas vaulted ceilings; the green the ductwork and the blue the in-line fan. I was experiencing 10 degree differences between the living/dining/kitchen and the bedrooms. Additionally, the bed rooms wouldn't begin to warm at all untill the living room was 80f. I reasoned that all of the heat was being trapped up infront of the stairwell, and once down the hallway (14ft) would immediately begin to rise up since the ceilings there are high aswell, requireing alot of heat to make it down to "living" space. The little corner fan I installed at the hall entrance was working, but not enough. So I began to dream...

Up to the double T (I bought 2 split them and joined the halves) is 8". Beyond it 6", I figured I needed the reduction to "stall" the air enough to get it to all three rooms. I was worried that 8" all around would result in all the air being moved only in a straight line. As I was installing it, I discovered that the fan wasn't even necessary, each register hole I cut I was immediately followed by being washed over by warm air (w/o ductwork!). I bought everything at Home Depot including the fan. I used flexible insulated ductwork (I'm considering "upgrading" to rigid if I can figure out how to get it in that space without removing the entire hall ceiling). I cut a large hole in the hall ceiling to do all the work and get the large peices in.

Result: 5-7 degree difference (why I'm considering the "upgrade"). I really hate doing patchwork (I used a panel to cover the hole in the ceiling) but I think I'm going to have to bite the bullet and make a large hole above the stair well to install rigid duct work.
Click to expand...
 
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