Originally Posted by 360view
Our house has two floors with one central AC and the 2nd floor is always 5 degrees F hotter in Summer.

Our next door neighbor has a nearly identical house,
and when his single central AC died four years ago
he put in dual AC units serving a floor each and he tells me it works much better.

For us, however, we now hear two AC units starting and stopping independently, causing twice as often fan start noise. frown


Sometimes depending on the house and the system getting it rebalanced will fix that upstairs heat problem. The hotter area gets more cooling and the temperatures end up matching better.

Our house is a big L shaped bungalow so our problem was because of exposure one side was always too hot or too cold. So each section ended up with it's own system.