The bigger HVAC win, in my opinion, if you have time-of-use billing, is to crank the temp when power is cheap (usually overnight), and, assuming your house is relatively well insulated, letting it ride through the rest of the day. This does lead to some funny things like the fact that I use heavier blankets in the summer than in the winter because I chill the house so far overnight, but for anyone whose climate is relatively moderate and with a relatively modern house, this can save quite a bit on power costs.
Admittedly, this will probably not work that well in a Minnesota winter, or an Arizona summer, but I think a surprising number of people could benefit.
Admittedly, this will probably not work that well in a Minnesota winter, or an Arizona summer, but I think a surprising number of people could benefit.