Reverse HVAC register fans?

[Boris]

I have a woodstove downstairs that heats up the 1st floor of the house very nicely. Unfortunately it does very little to heat the 2nd floor. The woodstove is on the opposite side of the house from the HVAC return so running in "fan only" mode doesn't do much.

Is it ok to put a couple fans into the HVAC returns in the room w/ the stove and pump some hot air into the system (while the main HVAC fan is OFF). I understand that its not the most efficient way but will it get some of the very nice hot air moving around the house?

Other thoughts, ideas?

I've tried the floor fans, ceiling fans, etc.. but there is only 1 fairly narrow stairway that goes to the 2nd floor and there just isn't enough circulation to evenly heat the house.

Boris.

 

[mellow]

Unless you have some very well insulated duct work most of the heat is lost, not to mention it will take quite a few CFM's to get that air moving which equals noise. Not sure what you do in that room but a loud fan blowing into the vent would be counter intuitive if you ask me.

 

[MDFisherman]

without knowing your system setup, simply adding a couple of fans to say an 1 or even 2 - 8" round returns would not provide a big enough pathway for the air to move at a slow enough speed to make it loud/annoying/intrusive. Not to mention if you're returning air it should be passed through a filter. You would also want to block off the coil so your not blowing dirty air across it.

It is not a feasible idea, especially if you do not have a good working knowledge of ductwork and air balancing.

If you really want to get the upstairs hot you can add another woodstove upstairs... Another idea would be to cut some holes in the floors with their own fans to move air. I believe that that topic has come up before you can do some research.

 

[TradEddie]

I've tried the floor fans, ceiling fans, etc.. but there is only 1 fairly narrow stairway that goes to the 2nd floor and there just isn't enough circulation to evenly heat the house.

Have you tried floor fans blowing cold air into the stove room, or pointing down the stairs? I've had good success with this, but I don't like tripping over floor fans. Also, if you can close some supply registers in the colder rooms and run the furnace fan, this forces more (cold) air out of the registers in the warm rooms, driving more of the warm air out or up to other rooms. Trying to move warm air while keeping it warm doesn't work, you don't have that problem moving cold air, and its easier to move.

Depending on your house air-tightness, cracking a window downstairs and another upstairs can also help draw warm air upstairs, the reasons are complicated and even disputed, but isn't it worth a try?

TE

 

[begreen]

I would not unbalance the system by closing off registers. That can cause the blower to race which can lead to premature failure. Besides, the duct losses would most likely negate any small gains. The issue is that the wood stove is an area heater. Upstairs is too far away from the heat source. And some houses are not well designed for convecting heat. You can try putting a table fan at the top of the narrow stairs pointing down and run it on low to see if that help accelerate convection to the upper floor, but with a small opening the results may only be a few degree gain. My guess is that a couple oil filled radiators or baseboard heaters may be a better solution. Or consider a modern wood furnace attached to the central heating system.

 

[TradEddie]

I would not unbalance the system by closing off registers. That can cause the blower to race which can lead to premature failure. Besides, the duct losses would most likely negate any small gains.

If it was that easy to damage a furnace fan, supply registers would not all come with dampers. I didn't suggest closing return registers (although I've happily tried that myself, with appropriate manometer in place). Running the furnace fan to drive air into the stove room thereby driving the hot air out means that duct heat losses are not a concern. You are of course correct that it probably won't work very well anyway.

TE

 

[Backwoods Savage]

Welcome to the forum Boris.

We feel for you. A lot of folks assume that hot air rises, and it does. However, getting that hot air from one floor to the other simply does not work well in most situations. In addition, if the basement walls are not insulated, that will draw most of the heat from the stove with no extra to go up. Best solution would be to install a wood stove on the level where the heat is needed or maybe we should say, where you spend the most time. Good luck.