When the weather gets cold, a thermostat's thermometer will sense the cooling temperature in your home and activate the furnace to increase the heat; and, when the weather is hot, the thermostat will turn on your air conditioning to provide some relief, according to the trigger temperature you set. One option is a TopTech programmable thermostat. It has a touch-screen digital display with a glow in the dark light button. You can easily adjust a TopTech thermostat to suit your heating and cooling needs.
Touch the "Heat" option in the "System" section of the display to turn on the heat mode, or touch the "Cool" mode to turn on the air conditioning mode. Touch "Off" to deactivate both heating and cooling, and touch "Auto" to turn on heating and cooling automatically as they are needed.
Touch "On" or "Auto" in the "Fan" section of the display. Leaving it set to "On" causes the fan to run all the time, and setting it to "Auto" makes the fan cycle on and off when the heating or cooling is activated.
Press the "+" or "-" buttons on the display to select what temperature you want the thermostat to maintain in your home. If you set it to 72 degrees F, for example, and the current temperature is 66 degrees, the furnace will turn on until the home is warmed to 72 degrees. If the current temperature is 83, the air conditioning will turn on until your home cools down to 72 degrees.