There are various schools of thought as to the best way to run the thermostat fan in an HVAC unit. Some believe it’s more efficient to set it to “auto” while others believe leaving it to run constantly is easier on your system. The truth is, there are pros and cons to both settings.
Setting the Thermostat Fan to “On”
Pros: Leaving the fan switched to “on” means that air is being cleaned as it is pulled through your filtration or UV light system. It also more evenly heats your home, as warm air is constantly being moved through the ducts. And lessening the number of times your fan stops and starts helps reduce wear and tear on it and helps it last longer.
Cons: Running your thermostat fan constantly without the use of a variable speed motor can cost much more every month. This sort of use also makes the filter clog up more quickly. And in the winter it will feel as though the air coming through the vents is cold, even though it will be the same as the space temperature.
Setting the Thermostat Fan to “Auto”
Pros: This method uses less energy. Since the fan only runs when the furnace is heating the home and turns off once the temperature has been reached, this setting keeps the fan running the least amount of time. This also helps the furnace filter to last longer, since less air is being pulled through.
Cons: Heated air is less evenly distributed, since the fan stops moving air throughout the home. This stopping-and-starting activity also wears the fan down more quickly.
The best option is to invest in a new thermostat, since many now have a “circulate” option. This allows the fan to be set to run a certain amount of time every hour in order to even out the home’s temperature and to keep cleaned air circulating.
NisAir Air Conditioning has been helping homeowners in Martin, Palm Beach and Indian River Counties run their HVAC system more efficiently since 1973. Contact us for help with your own HVAC needs.