Another heat through ductwork…kind of.

[Ohiowoodstove]

Okay so my house is set up pretty weird. Our living room which houses are wood stove has a vaulted ceiling. The rest of the house has low ceilings but for some reason whoever built our house decided to create a hallway that juts out with a shelf above it. So I find that all of our hot air gets trapped up in the peak of the ceiling with nowhere to go. The only nice thing is that the main air return is actually located up by the peak where all the hot air is. I’ve attached a few pictures to help give an idea. The return ductwork is a pretty straight shot back and each bedroom has a cold air return located on the upper part of the walls. Here’s my question. I think, if I can attach an exhaust fan to where the main cold air return vent cover is and force the hot air into the bedroom and essentially back feed it into the rest of the house I can help get the back rooms warmer. Is this idea genius or stupid? I should also add that although the cold air returns are located toward the ceilings my main duct work runs through the crawl space so I don’t think it would be worth just trying to kick the main furnace fan on. If this idea won’t work, does anyone have other suggestions? I’ve tried fans at the end of the hallway pointed either direction and didn’t see much change.

 

[begreen]

Sounds like the crawlspace ductwork needs to be insulated if that is an uninsulated space.

 

[Ohiowoodstove]

All ductwork is insulted in the crawl space. All cold air returns runs through insulated attic. I just know I’d lose my hot air through the ductwork running the furnace fan. Back feeding the cold air return is a shorter shot to push the hot air.

 

[begreen]

If it's all sealed and insulated, try it with the furnace fan for a few hours and see how it works.

I am concerned with the exhaust fan idea. If it restricts the return, it could burn out the furnace blower. It would also be noisy.

Are there ceiling fans in the vaulted ceiling area?

 

[brenndatomu]

Have you tried placing a small fan on the floor at the cold end of the house, pointing back toward the stove (down the hallway?)
When you push the down low cold air out of that area, the higher warm air will be pulled in to replace it (creating a loop) and a ceiling fan running in winter mode (backwards) in the room with the stove will keep the air from stratifying in there.

 

[Ohiowoodstove]

There is one right at the peak essentially right above me where I took the photo. I will also add I would remove louvers from any exhaust fan installed. I was also concerned about restricting the return airflow, but I don’t think an open mount fan would be any more or less restrictive than the cover that’s already installed.

 

[Ohiowoodstove]

Have you tried placing a small fan on the floor at the cold end of the house, pointing back toward the stove (down the hallway?)
When you push the down low cold air out of that area, the higher warm air will be pulled in to replace it (creating a loop) and a ceiling fan running in winter mode (backwards) in the room with the stove will keep the air from stratifying in there.

Yes I have tried that. I have a temp and moisture monitor and I have sensors placed in each room so I can monitor the changes I’m making so far I haven’t found anything to cause any noticeable difference.

 

[begreen]

The ceiling fan should help move that hot air. Is it being run in summer (down) or winter reverse (up) mode?

 

[Ohiowoodstove]

The ceiling fan should help move that hot air. Is it being run in summer (down) or winter reverse (up) mode?

Yessir I change it with the seasons. I think what’s really causing the airflow issue is the ledge above the hallway.

 

[brenndatomu]

Any fans should be run on low too...if you move too much air it will just feel like a cold draft, even if the house is warm

 

[begreen]

What is the temperature of the air at the peak of the ceiling?

I suspect this idea will not work because the air will take the shortest route without resistance which is straight back to the furnace and thru the furnace to the supply duct. There would need to be a damper in the return duct to prevent this. The damper would have to be automated so that it always opened when the furnace was on.

 

[Ohiowoodstove]

Last year I was getting somewhere around 98 up at the peak. The furnace ductwork is actually on the side of the cold air return ductwork toward the center of it. And it actually goes into the filter box. So although I would be losing some warm air through it I believe most would be pushed into the rooms.
I guess my reasoning behind this idea is, the heat is already up there. If I can push it through about 20ft of return ductwork it’ll be a shorter and most efficient path than running it from the attic all the way through the furnace, into the crawl space and back up the floors.

 

[begreen]

Consider making a temporary shelf under the return grille and put a box fan on it connected to an extension cord for testing. Tape a sheet of paper over the filter to block it and flip off the furnace breaker.

 

[RockyMtnGriz]

Consider making a temporary shelf under the return grille and put a box fan on it connected to an extension cord for testing. Tape a sheet of paper over the filter to block it and flip off the furnace breaker.

I was thinking this, or maybe a fan or blower on a step ladder.

Also, you could try blocking the returns in the distant rooms to force the air to come back to the stove room so it can be heated. With returns open in the unheated rooms, you're probably just recirculating a good portion of unheated air. You'd have to be careful that you aren't starving the blower for return air, but if you had a lower blower setting, that probably wouldn't be an issue. If you don't, it might still be okay, depending on your return setup. Some would be careful and want a manometer check, but I'd say it's good to go if the outlet air flow isn't noticeably changed with the distant returns blocked.

I block my downstairs returns when I'm cooling. It helps bump up the return air temp substantially when all it can pull is the warmer air from upstairs and seems to help with the heat transfer. I run the blower on low, and it works just fine.

 

[Woodsplitter67]

You need to run a flex duct with an inline booster fan and this would be separate from you existing HVAC system. I installed such a system years ago during a home remodeling project. I installed a wall switch ro turn it on and off. I have an intake at the ceiling where the air is warmest going to a 14 inch duct booster fan that is split up between the 3 farthest areas the kids bedrooms and the master bathroom with vents in the ceiling for the warm air to blow. You'll get alot more warm air this way its also more efficient. I dont run mine all the time, just here and there when it gets really coold

 

[Ohiowoodstove]

You need to run a flex duct with an inline booster fan and this would be separate from you existing HVAC system. I installed such a system years ago during a home remodeling project. I installed a wall switch ro turn it on and off. I have an intake at the ceiling where the air is warmest going to a 14 inch duct booster fan that is split up between the 3 farthest areas the kids bedrooms and the master bathroom with vents in the ceiling for the warm air to blow. You'll get alot more warm air this way its also more efficient. I dont run mine all the time, just here and there when it gets really coold

This is essentially what’s already there. It’s just part of the cold air return. Minus the fan. I guess I could run a whole new system separate from the existing ductwork but why? It’s not like I’m going to be back feeding while the ac is running. But now that I think about it that wouldn’t be a bad idea either. I could force an imbalance of air coming from the room with the wood stove. Almost like the concept of blocking the cold air return in the back rooms as mentioned above.

 

[Woodsplitter67]

This is essentially what’s already there. It’s just part of the cold air return. Minus the fan. I guess I could run a whole new system separate from the existing ductwork but why? It’s not like I’m going to be back feeding while the ac is running. But now that I think about it that wouldn’t be a bad idea either. I could force an imbalance of air coming from the room with the wood stove. Almost like the concept of blocking the cold air return in the back rooms as mentioned above.

Id run a closed.. dedicated system as this will be warmer then running your actual HVAC system.. flex duct is insulated a bit smaller and will have less heat loss. the in line fan will also draw less electricity. this is not really a hard project. You dont want alot of heat loss in the system as it will struggle to heat the rooms you have.. Your HVAC system will not take the warm from the ceiling and blow it DIRECTLY into the rooms you want to heat. The flex duct booster fan system will..

 

[begreen]

This is essentially what’s already there. It’s just part of the cold air return. Minus the fan. I guess I could run a whole new system separate from the existing ductwork but why? It’s not like I’m going to be back feeding while the ac is running. But now that I think about it that wouldn’t be a bad idea either. I could force an imbalance of air coming from the room with the wood stove. Almost like the concept of blocking the cold air return in the back rooms as mentioned above.

I have seen more than one blower motor toasted by people doing this. The imbalance can cause a change in the design static pressure causing the motor to race. I like the closed design system better.

Woodsplitter, did you ever try running it in reverse, pulling air from the bedrooms, and dumping it up high at the ceiling?

 

[mikefromiowa]

In your picture of the hallway with the shelf above it, is that the cold air return behind the bird cages? (red arrow pointing to it)

If so, I think your idea of using a fan to push warm air through the cold air return to the bedrooms is doable. If a box fan fits on that shelf, it would be easy enough to try and see what happens. Similar idea to what a couple of others have already suggested. (I think you would need to keep the bedroom doors open a bit so there is a return air path through the hallway for the cooler air to flow back to the stove room.)

 

[Woodsplitter67]

In your picture of the hallway with the shelf above it, is that the cold air return behind the bird cages? (red arrow pointing to it)

View attachment 302606

If so, I think your idea of using a fan to push warm air through the cold air return to the bedrooms is doable. If a box fan fits on that shelf, it would be easy enough to try and see what happens. Similar idea to what a couple of others have already suggested. (I think you would need to keep the bedroom doors open a bit so there is a return air path through the hallway for the cooler air to flow back to the stove room.)

its not going to work.. yor filling the entire duct system with air.. there is nothing to direct the warm air only to the bedrooms.. the heats going to go to the path of least resistance.. which is to stay in the cold air return.. the easiest way is to create a Dedicated system.. again this will insure the warm air goes directly to the rooms needing the heat. and the air that is getting to the room is actually warm enough to heat it..

 

[Ohiowoodstove]

In your picture of the hallway with the shelf above it, is that the cold air return behind the bird cages? (red arrow pointing to it)

View attachment 302606

If so, I think your idea of using a fan to push warm air through the cold air return to the bedrooms is doable. If a box fan fits on that shelf, it would be easy enough to try and see what happens. Similar idea to what a couple of others have already suggested. (I think you would need to keep the bedroom doors open a bit so there is a return air path through the hallway for the cooler air to flow back to the stove room.)

Yes, that’s the return from the stove room.

its not going to work.. yor filling the entire duct system with air.. there is nothing to direct the warm air only to the bedrooms.. the heats going to go to the path of least resistance.. which is to stay in the cold air return.. the easiest way is to create a Dedicated system.. again this will insure the warm air goes directly to the rooms needing the heat. and the air that is getting to the room is actually warm enough to heat it..

Just for clarification check out the last photo posted. I drew out the cold air return pipe and an arrow pointing to the returns in the other room. The setup is a long duct running the length of the house. Probably 20ft with offshoots to the right or left that come off the main pipe. These are very short. There is also an offshoot to the right that goes to the filter box for the furnace. A fan from the stove room cold air return is at the end of the duct work and would push the air straight back the pipe and into the other rooms. Granted some would be pushed to the filter but I don’t think much. For the record I am not disagreeing with you at all and an isolated system may be the best option im just trying to make sure I am explaining the setup clearly.

 

[Woodsplitter67]

Yes, that’s the return from the stove room.

Just for clarification check out the last photo posted. I drew out the cold air return pipe and an arrow pointing to the returns in the other room. The setup is a long duct running the length of the house. Probably 20ft with offshoots to the right or left that come off the main pipe. These are very short. There is also an offshoot to the right that goes to the filter box for the furnace. A fan from the stove room cold air return is at the end of the duct work and would push the air straight back the pipe and into the other rooms. Granted some would be pushed to the filter but I don’t think much. For the record I am not disagreeing with you at all and an isolated system may be the best option im just trying to make sure I am explaining the setup clearly.

the air is going to follow the path of least resistance.. its not going to go into a small pipe leading to the bedrooms when theres a larger pipe for the air to move to.. in order for the air to move into the smaller pipe and into the bedroom.. how are you forcing the air to move that way. as a cold air retur gets longer and more cold air returns connect into it the larger the trunk has to be to accommodate more air.. my cold air return is twice as big on one side of my house closest to the furnace..

 

[Ohiowoodstove]

I’ll have to get up in the attic and snap a picture. From what I remember if I’m correct there is one long pipe that is capped at on end the stove room vent on the other side, and openings for the rooms. Force air from the one end (stove room) and once it reaches the cap at the end there is nowhere else for the air to go except sideways into the openings for the rooms, or sideways into the filter box. It really is set up exactly how you describe your isolated system inside the attic. But I could totally be missing something you’re trying to tell me. I’ve never been called the sharpest in the room!

 

[Ohiowoodstove]

You need to run a flex duct with an inline booster fan and this would be separate from you existing HVAC system. I installed such a system years ago during a home remodeling project. I installed a wall switch ro turn it on and off. I have an intake at the ceiling where the air is warmest going to a 14 inch duct booster fan that is split up between the 3 farthest areas the kids bedrooms and the master bathroom with vents in the ceiling for the warm air to blow. You'll get alot more warm air this way its also more efficient. I dont run mine all the time, just here and there when it gets really coold

Okay woodsplitter I think you've got me thinking good and hard about this and I think i'm agreeing with you now. I did try a boxfan up on the main return but I couldn't get it seated all the way due to the pitch of the ceiling but it did seem to work ok. stove room being 73, closest bedroom at 69 and furthest about 66. I would still like to see more even temps. the cold air return maybe just slightly better than running the furnace fan. the box fans pointed toward the stove don't seem to do much of anything for me. (I am monitoring temps in each room via sensors and temp display). I think the isolated system, pain in the butt aside will probably be most efficient.



So here's my question. How do you like your system? how well does it work? If i can get the 73 degrees in the stove room to push enough warm air to get all the bedrooms at 69 or 70 i'll be happy. again, this isn't a long run. maybe 25 foot or less.

 

[Woodsplitter67]

Okay woodsplitter I think you've got me thinking good and hard about this and I think i'm agreeing with you now. I did try a boxfan up on the main return but I couldn't get it seated all the way due to the pitch of the ceiling but it did seem to work ok. stove room being 73, closest bedroom at 69 and furthest about 66. I would still like to see more even temps. the cold air return maybe just slightly better than running the furnace fan. the box fans pointed toward the stove don't seem to do much of anything for me. (I am monitoring temps in each room via sensors and temp display). I think the isolated system, pain in the butt aside will probably be most efficient.



So here's my question. How do you like your system? how well does it work? If i can get the 73 degrees in the stove room to push enough warm air to get all the bedrooms at 69 or 70 i'll be happy. again, this isn't a long run. maybe 25 foot or less.

How do I like it.. It works. As stated, I don't use it all the time just in the dead of winter here and there. When its on you can barely hear it and it moves the warm air well. Have I ever been disappointed with it, never.. Am I glad I installed it yes. The air coming out is warm and heats the rooms well.