“You absolutely need a separate, fast-acting thermometer to set up this thermostat. The suggested cycles per hour are only a starting point. My system, older gas forced air, was supposed to be 5 cph. With the thermostat temperature set at 74, the thermostat called for heat at 71, and when the cycle completed the room temperature was 78. A 7-degree difference. The cycle took about 14 minutes but the temperature on the front of the thermostat never changed from 74.”