I'm thinking about buying a new Honeywell RTH7500D thermostat for my Lennox heating/cooling system in my home. I like the idea that it will "auto change from heat to cool". It also has a 7-day programmable feature that I like. The problem that I am trying to solve is the west wall of the house has lots of windows. Even on a cool sunny day, this side of the house is warm in the afternoon and will warm the rest of the house, so we switch on the AC. But at night, it cools off and we need heat again. This is more of a problem in spring and fall (6 months of the year). Has anyone tried this thermostat? Does it really work like the manufacturer promises?