[dmx1970]

We have a 2-story contemporary with a central foyer that encompasses both floors. In the summer, the bedrooms upstairs are noticeably warmer than the downstairs-- especially the master bedroom. I believe this is due to the thermostat being on the first floor so the first floor cools and turns off the AC before the 2nd floor is cool. Would you recommend a 2nd AC unit in the attic to make the house 2-zone?
Also, on cooler nights we like to keep the windows open and are considering installing a whole house fan. Would a whole house fan situated in the two story foyer be able to exchange the air in the house? Or does the large volume of the foyer decrease it's efficiency?
Thanks very much!

 

[Marty1Mc]

I don't think the foyer will affect the efficiency that much. It will pull the air from whereever and the distance the open window is from the unit will affect how much flow.

I had one in my house in Maryland. It was in the upstairs hallway between the bedrooms. I found I hardly used it and I spent a decent amount of time installing it. Once the AC is on the air is dehumidified. But, when I would turn it on at night, the air coming in was humid (more humid than I liked). Plus it wasn't as cool as the AC.

I would try a couple of things. First, maybe have your system rebalanced by an HVAC guy and have more air directed upstairs. Also, consider installing ceiling fans.

 

[beenthere]

A second unit for the second floor would help. Of course, your current unit will then be over sized for teh first floor only.

A whole house fan in the foyer should work fine, as it will draw air from what ever windows are open.