Your thermostat will always be "on", but it will call for heat or cooling at different times depending on the temperatures that you have set. When the Honeywell thermostat senses that the temperature in the room falls below 1/2 of a degree below the set "heat" temperature, the heat will turn on. When the temperature in the room rises 1/2 of a degree above the set "cool" temperature, the cooling will turn on. Both the heat and the cool will shut off when the desired temperature has been reached.
The TH6110D1005 and many other Honeywell thermostats can be found at www.supplyhouse.com
