Our heating and AC doesn't reach our top floor. We have a basement, first floor and second floor. During the summer we use window AC, but in the winter it gets incredibly cold up there. At one point it was 40F. We put in a fan to pull up the air, but that hasn't helped. We want to fix it before the winter. Any ideas as to what is making the air not reach the upstairs level?

If there were some way to install a return air duct in the upstairs area then the a/c system could help the situation.

We actually have 3 returns up there, but it doesn't seem to help.

An option might be to install a duct booster fan in the supply duct to the upstairs.

We have one up there, but it hasn't helped much with the AC. Will it work better with the heat? I'm not sure how they work.

You would think this would be the warmest room in the house because heat rises, is ths room open to the rest of the house?
A duct booster fan installs in the duct and simply assists the air by pushing it along.

Is the duct work located in an unfinished attic? Have you insulated the duct work? It not, the extreme heat and cold in your attic could cause the air temperature to change dramatically before it enters the room through the register. This, coupled with a duct booster fan may be what you need to fix the problem.

Duct insulation is very easy to install, and is available at home improvement stores, so you won't need to hire someone.

Thanks for all the advice! I'm actually renting it with two friends, and our landlord keeps telling us there is nothing else they can do, but I feel there has to be something because I know other people with the same house, but their upstairs heats up. I will bring up your suggestions to them!