I use a Honeywell FocusPRO 6000 thermostat. It communicates with a 18 seer two-stage KeepRite air conditioner and a two-stage 96% AFUE KeepRite furnace. Installed by an industrial HVAC installer that installs systems at hospitals, factories, universities etc (not a typical home installer).

Cream of the crop. I talked to a HVAC guy at a wedding recently and he almost splooged in his pants when I described our heating and cooling system.
I’m armed and I’m drinking. You don’t want to listen to advice from me, amigo.

-Max Payne