I'm in a narrow, vertical, townhouse style three story house. My upstairs bedroom gets too hot, and downstairs gets too cold.

I found I could fix the downstairs problem by running the HVAC fan full time. I think it works because there are quite a few downstairs vents. The air intake and the thermostat are both on the second floor, and by leaving my fan running more air is mixed from the different floors.

However, my third floor consists of just a single bedroom and there's a single vent. The room is kind of "suspended" above my living room, which has a high ceiling.

What are my options for fixing the third floor problem? I wonder if I could install some kind of fan into the wall, that would blow hot air out of the third story bedroom and into the living room (as there's a shared wall), so it would pull cooler air up the stairs and into the bedroom. That way more mixing would occur and my room temperatures could average out.

Or is that a bad idea? Should I just hire someone to balance the vents?

  • I hate to say it, but this really is too broad for DIY, both the site and for you. I would pay a pro to balance your HVAC. A simple fan is unlikely to solve the problem. – Machavity Jan 31 '19 at 19:25
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    Don’t forget that you’ll loose the privacy when you cut the opening. Sound will travel both ways. – Lee Sam Jan 31 '19 at 20:33
  • Is this an open plan where it's one big tall space? – Harper - Reinstate Monica Jan 31 '19 at 20:59

It sounds like the living room is a very tall space. It is normal for there to be significant thermal separation in such a tall room, befause heat wants to go up. Tall rooms are a cultural indicator of wealth, which is one reason people like them; however the "wealth" part is that they cost more to heat.

It can help to have some sort of fan stirring the air. It does not need to be a breezy blasty fan, who wants that in the winter, right? It just needs to stir the air enough to prevent stagnation. We have a 34,000 square foot 30' ceiling building with 3 fans stirring the air, it doesn't take a lot and you don't really feel them.

As for balancing the vents, you don't need to hire a guy to work the little knob that closes the vent upstairs. You can do that yourself and just use trial/error - every time, bump it less distance than you did before, eventually you will settle on balanced. If your vent does not have a knob, get one that does.

Brace yourself for this: the vent setting that works in winter won't work in summer when the A/C is running. You'll have to change it, probably opening upstairs 100% and partially closing downstairs vents.

  • I live in the south, so our biggest bills are in the summer (by far). Wouldn't it make sense to NOT stir the air in the summer, and let all that hot air stay up there so the temperature gradient across the roof is lower? – Slothario Jan 31 '19 at 21:56

It sounds like your HVAC is conditioning the air pretty well, it's just not circulating (as you stated). If the air your are moving from that bedroom is moving at a decent rate, it should cause the air in your living room to circulate better. You want that hot air to be drawn or pushed down lower into the living room. If you also have a ceiling fan in the living room, the air would circulate even better.

I installed this Broan 8" room to room fan when I converted our garage to a bedroom to prevent running ductwork in a confined space. It moves nearly 200 cubic feet of air per minute. It was very easy to install and has an adjustable speed so you can get the setting just like you want it. I hardwired it into a junction box in the ceiling. However, you can also buy models that have a corded plug at Home Depot, Lowe's, etc. You just need to install those close to a dedicated outlet.

I also installed a louvre in the bedroom door for the HVAC to pull air back out of the room. Worked like a charm for me. This shouldn't be an issue for you.

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