When your heating and cooling system’s fan is set to ‘on’ it operates continuously. The compressor continues to periodically cycle on and off automatically to cool and dehumidify your home when the fan is set to ‘on’ or ‘auto’ on your thermostat. The difference between the two settings is that with the fan ‘on’ and continuously circulating the air, the temperature stays more even throughout the house by clearing out pockets or layers of static, warm air.
Consider the ever-present thermostat – a staple of American households for decades. It usually takes the shape of an unassuming box on the wall, but that modest device controls the comfort of your family on the coldest day in January and the hottest day in July.
A thermostat is a temperature-sensitive switch that controls a space conditioning unit or system, such as a furnace, air conditioner, or both. When the indoor temperature drops below or rises above the thermostat setting, the switch moves to the “on” position, and your furnace or air conditioner runs to warm or cool the house air to the setting you selected for your family’s comfort. A thermostat, in its simplest form, must be manually adjusted to change the indoor air temperature.