Digital manual heating/air conditioning thermostat, straight forward display & basic buttons keep operation simple, backlit display shows current room temperature & set point temperature simultaneously, /- 1 degrees temperature control, auto change from heat to cool, includes change reminders for low batteries, program is retained in memory & event of a power outage, fahrenheit or celsius temperature display, compatibility chart 24v heating & air conditioning systems single stage heating & cooling yes, multi-stage heating & cooling yes, heating only yes, cooling only yes, furnace warm air yes, central air conditioning yes, heat pump without auxiliary heat yes, heat pump with auxiliary heat yes, hot water yes, steam or gravity yes, 750mil yes, gas fireplaces 24 v yes, electric baseboard heat 120-240v - no.