I have a programmable thermostat, and I cannot adjust the differential setting. I am looking for a programmable thermostat that I can adjust the differential setting up to 3 degrees. For example, the temperature is set at 70 degrees. In the winter, the furnace will kick on when the temperature falls to 67 degrees. It will then run until the house is heated to 70 degrees. It will then shut off until the temperature falls back down to 67 degrees. This is preferable than having the furnace kick on and off every 30 minutes to maintain a constant temp of 70 degrees. Too much wear and tear on the furnace and AC.