Honeywell RTH8500D 7-Day Touchscreen Programmable Thermostat ware Imported Universal Application - works with conventional and heat pump systems up to 2H/2C, it's one thermostat for nearly every application Program is retained in memory in the event of a power outage Includes change reminders for filters and low batteries Separate programming for each day of the week - 4 periods per day.To avoid possible compressor damage, do not use auto changeover if the outside temperature drops below 50F (10C). Maximum comfort - Smart Response technology learns the amount of time a system needs to reach a desired temperature and adjusts accordingly Precise temperature control of +/-1 Degree for consistent comfort