Somewhere I read (and now I have found a link) that all programmable thermostats lost their Energy Star rating due to the fact that more people lost money than saved money after implementation.
Sounds more like people just didn't know how to use them to me but here is the article I found.
Programmable thermostats no longer part of Federal Energy Star program The understanding I got from the guy that installed my system is that you don't want your system to short cycle or have large swings in temperature programmed from one period to the next. People with digital thermostats like to alter their temperatures a bit too much. He told me just to set it and leave it alone. Furnace and air conditioner will automatically switch over. Ideally with a system like mine to get maximum efficiency from the air conditoner you actually want it to run pretty much all day in the lower stage. It will kick on to stage-two to "catch up" briefly but that doesn't last long. Constantly altering the temperatures can hurt more than help. In this case would cause the air conditioner to run at the higher stage more than it needs to.
