Moving warm air

My stove is in the living room, which has a 12 ft cathedral ceiling. On the other side of the wall is our bedroom with conventional 8 ft ceilings. I would like to install an inlet vent at the peak / \ of the wall in the living room, connected to a blower (can be installed in the attic above the bedroom), which will then blow down through a duct in the wall, discharging through a vent at the base of the wall in the bedroom. It will be a vertical installation, all located in one wall bay, which is framed 2x6, 16 OC.

Questions:

1. How many air exchanges per hour would you plan?
2. How can I minimize the noise? <------This is really important.
3. Can I use an axial inline fan (cheaper), or should I use a centrifugal blower?
4. Should I use 4 or 6 inch duct?

Or, any better ideas?

Thanks for any input you may offer.

Greg

 

Just sharing my experiences.

The larger the duct the better. Small ducts mean higher velocity to flow equal amounts of air. Higher velocities equal more noise.

In-duct fans that I use are not quiet. Probably partly do to the fact that they are contained in essentially a sound chamber. There may be better and quieter fans out there rather than the ones I bought from Menards.

A direct path will result in a need for a smaller fan or at least more cfm from the same fan (less bends less resistance).

We have gotten use to the sound as it is constant and it becomes just background noise.

I would try to dump more cold are into the stove room instead of trying to move hot out. Consider blowing cold floor air from another room into the hot area. Cold air will displace hot air.

That being said cathedral ceilings aren't easy to move air out off and into an regular ceiling room.

 

Moving warm air downward is against it's nature.

Perhaps two simple wall grilles one low/one high in the bedroom wall next to the stove area?
Unsightly, but probably more effective than your proposed system. No fans either...quiet.

 

I agree with that because you need to move the cold air out of that room.
Cold air is much easier to move because it is more dense.
Put in a vent down by the floor and put a fan or something there, moving cold air out of the room on low speed, same thing by the ceiling of the other room, moving warm air into the room.
I'm sure you may be able to think of other types of fans or whatever but, you know, maybe just something like these.
doorway fan - Google Search

if you were to just put a vent on the floor with a fan pushing cold air out of that room, I think you would see a big difference just with that

 

The problem is that the "hot" room has a cathedral ceiling, 9 ft on the sides and 12 ft in the peak. The "cold" room has a standard 8 ft ceiling. Putting a vent at 8 ft will not get the hotter air up high, though it certainly would help.

Greg

 

I hate to be the party pooper but I think your plan won't work too good. ALWAYS push the cold air back towards the stove. This method creates a natural convection. With the cathedral issue I bet a ceiling fan mixing the air in that room would be most beneficial. A small fan in the bedroom pointing along the floor towards the door would push the cold to the cathedral room and come back in the top of the doorway as the room temp of the cathedral room.

I hope that all made sense.....

 

You don't ALWAYS have to move the cold air. Everyone on here seems to think this is like a miracle discovery, but the difference is only a little, and more because of the placement than the cold vs warm air. Sure it's better, but just a little. Most people have fans on the floor where it is coldest anyhow. If you tried to move warm air away from the stove like so many try by placing small fan on the floor, it doesn't work so well at all, since it is the coldest air at the floor and probably fighting against natural convection loop. If you had a small fan at the top of a doorway or hallway trying to blow warm air, it will still work alright. The big issue is stratification of the hot air, which moving cold air at floor level won't help much for. I fight this too with my great room that has the stove in it - 17' at the ends and 19' in the middle. A lot of heat goes straight up and stays up. Trying to move cold air at floor level is only going to pull slightly warmer air a few feet up and leave the warmest air alone to heat the ceiling. I can't move much heat at all through the doorway to the other side of the house. Even in fairly mild temps like the mid 30's last week running just the one stove let the next room over get down to 58-60F, using a fan at the doorway. Had to put a stove in that next room, just could not effectively heat it otherwise (poorly insulated and drafty too). I use two large ceiling fans in the great room to mix up the stratified air, that helps a little but still the upstairs area that opens up to it is much warmer than the nearby areas of the first level despite running the fans up to a medium is level (quite a lot of flow since they are large fans). I haven't actually measured the air temp but I'd guess the air near the ceiling to be well more than 10F warmer than the air down at the height of the first floor doorway. (using IR on the ceiling versus the floor surface temp was 16F difference). Much much more if I didn't have the fans going probably. It's not a great setup and I really hope to build a new home or buy one that is or can be modified to be better as a single stove heated home.

As for your question bushpilot, if it were me, I might try something like you're suggesting. But I wouldn't duct it all the way to the floor, maybe entering the room near the ceiling or at least in the upper half, and then place a small fan facing on the floor in the doorway to push the colder air back out of the bedroom into the living room and form a loop. I'd probably need to see floor plans though. I'm not sure if it will be worth the fuss though, but good luck if you try and be sure to report back. I didn't think ducting and a fan would be enough to heat my adjacent room and the couple rooms off it so I just went with the second stove. but just for one bedroom maybe it would work.

 

Miracle discovery?

Im not sure I've ever heard anyone say it's a miracle....unless they are referring to Miracle Whip, which is good on sandwiches.

 

This is what I think as well, the difference is marginal at best.

For me, as for you, the primary task is to get the warm air down to people-level, secondarily to get it to the other rooms. What I have decided to try is the the Thernlund AS1, which I will install at ceiling level (12ft) in the "warm" room, and likely at floor level in the "cold" room. They can be had for $129 on eBay.

Thanks for the input everyone.

Greg

 

I'm surprised you haven't - being on the forums longer than I... but lol. I exaggerate of course, and play devils advocate at times. It is good advice that often needs handed out, since it is counter-intuitive and most people aren't aware of it. It just doesn't fix every situation.

bushpilot - I wasn't aware they actually made an all-in-one product for this application. That's interesting, I'd be eager to hear how it works out.