Bathroom fan used for interior air circulation?
I’m looking into ways to increase air circulation within my house. The house is really only heated on the first floor — the upstairs just has some electric baseboard heaters. They will produce heat, but it’s expensive, and tend to make a room alternately too hot and too cold. We’d like to increase circulation such that some of the warm air from downstairs can end up upstairs and raise the overall temperature. The upstairs is mainly used for sleeping, so doesn’t need to be as warm as downstairs. Our current thought is to install a bathroom-type exhaust fan in the living room ceiling, with the “exhaust” being directed to a (new) vent into the upstairs hallway (directly above). The stairway would effectively serve as a cold air return. I’m leaning towards an exhaust fan both becuase of the ease of installation, and because they are specifically designed to be quiet. Most in-line duct fans don’t even seem to give noise ratings, and quiet is important — this will run between the living room and the hall outside the bedrooms. My main concerns are 1) whether such a fan would be quiet enough, and 2) whether an exhaust fan is suitable for this use — it will run many more hours a day than a bathroom exhaust fan usually runs. So…questions… 1) Will running a bathroom exhaust fan most of the time harm the fan and make it wear out too soon? 2) Is there a better alternative than can be used to pump warm air upstairs 3) Any brand/model recommendations? The NuTone ones look to have pretty low noise ratings, but there may be others I haven’t found. 4) Anything I haven’t thought of? In case it’s relevant…the house is well insulated and tight, with a heat exchanger/ventilator. We don’t have any ventilation problems, just interior circulation ones. We also have a conveniently located closet upstairs that we can grab a little room from if necessary, so don’t have to keep the ducting fully within the floor or wall cavity.
Replies
Although a bath vent fan will move air from point A to B, I would be inclined to use a product specifically designed for your purpose.
No first hand experience with these, but they are worth a look:
"AireShare Ventilators" by Tjernlund Products, Inc. - room to room or level to level.
http://www.tjernlund.com
Good luck,
Jim
The one concern I'd have
The one concern I'd have would be the life of the fan. Probably you should look for something designed to run continuously.
You may have tried this... but do you have a bathroom upstairs? If it has a fan, you could run that. It would create a vacuum in the upstairs, allowing the hot air to rise. If it doesn't, you could install one.
Maybe run another switch downstairs, so you can turn it on from there, or is there a thermostat that turns on when it gets cold?
Concerning the length of life for the fan, The motors of average exhaust fans can be changed out fairly easily. If you want something better, replace the bath fan with a continuous rated in-line fan in your attic (assuming you have one)
I think it's worth a try
I think it's worth a try because of the low cost of a bath fan. The main work will be running the power and duct; to replace the fan later on would be simple and cheap.
Panasonic also makes some very quiet, highly efficient bath fans.
I'm going to question your
I'm going to question your assumptions here, because you have a problem that no one else seems to have: Heat not rising!
This is what I understand from your post... Your upstairs is cold, but your downstairs is warm.
Now, normally what happens - and this IS the bane of most American homes - is that cold dense air falls to the lower floors and thin warm air flows upstairs. I hate Colonial style homes because the bedrooms bake in winter while you shiver in the downstairs living room, or in the summer you swelter in the bedrooms at night while the downstairs is 10 degrees cooler - where the thermostat is!
Is there something in your house that is keeping the hot air from naturally filling the upper floors? Is the upstairs only accessible with a closed stairway or elevator?
If not - if your house is constructed like everyone else's with an open stairway - then I think you may be loosing heat upstairs. If those electric heaters get too hot then too cold, it sounds like the heat isn't staying in those rooms!
Thanks for all the input. A couple answers to questions from different people:
While our stairway isn't "closed", it is in a narrow hallway, and you have to turn 180 degrees from the top of the stairs into the hallway back to most of the bedrooms. The (load bearing) wall between the stairway and the upstairs hall goes to the ceiling. It's not an open plan, and there isn't a lot of air movement. If it were more open, I'd try to put a regular ceiling fan at the top of the stairs to move air, but I'm not sure that would gain us much.
The house is pretty tight -- we had a blower door test done last spring, and I forget what the numbers were, but the conclusion is that we were good (which was kind of too bad, since there were no easy fixes suggested!).
I don't want to just turn on the exhaust fan in the upstairs bath, though that would probably move more air upstairs. We have a balanced ventilator (pulling air out of the kitchen/baths, and bringing fresh air into each bedroom and living room), and I think adding a continual exhaust fan to that system would cause problems.
I'll check into the Panasonic and Tjernlund product suggestions.
We have a balanced ventilator (pulling air out of the kitchen/baths, and bringing fresh air into each bedroom and living room), and I think adding a continual exhaust fan to that system would cause problems.
Maybe that fresh air is cooling off the bedrooms ??