We have a tri-level house where the middle (which is our living room) is the in-between level. When we turn on our A/C we find the downstairs to get pretty cold but the upstairs not so much. So, we've turned down the A/C further so it stays on and the upper level gets colder. We live in Southern California and we have pretty good sun exposure - especially the upper level (temps in the summer months can hit 100+). In the past we've closed the vents downstairs and had most of the air upstairs, but we were told not to do this from an AC expert that was there to look at something else. He said that we get good flow and that our A/C unit is performing well. BTW our thermostat is downstairs.

So, what can we do to get cold air both upstairs and downstairs? Should we not listen to this "expert" and close the downstairs vents or is he right and we need to find alternate solutions. Really, the idea of having the AC on longer is fine except that it gets pretty chilly downstairs and it's still only a little cooler upstairs so that is comformtable as well.