If your home's thermostat is like those in most homes, the fan setting is probably on "auto," which seems to be the default in most systems. But that begs the question, what does the "on" setting mean? This isn't an idle question since setting your thermostat fan one way or the other can make a big difference in energy bills and home comfort.
What's the Difference?
There are two main modes of operation in a central, forced-air HVAC system: the equipment that creates the cooling or heating, and the equipment and fixtures such as fans, ducts and registers, that distribute conditioned air throughout the home.
Setting your thermostat fan determines how the air distribution is handled. When the set to "on," the HVAC blower or air handler blows full-time, even when the cooling or heating isn't happening. When set to "auto," the fan only operates during heating or cooling
"Auto" Is Usually the Better Setting
While a few HVAC experts swear by setting your thermostat fan to "on," most agree that the "auto" setting makes more sense for energy efficiency and home comfort. They cite the following reasons:
- If your home is equipped with an oversized cooling system, it will cycle on and off frequently. During the "off" cycle, residual moisture will be left on the evaporator coil. If the fan is continuing to blow, it will re-absorb that moisture into household air, and your A/C will have to work harder to dehumidify the air.
- Around-the-clock fan operation uses more energy than a system that only runs the fan during active cooling and heating.
- Many people appreciate the silence when the fan turns off along with the air conditioner or furnace.
- If your home's ductwork has air leaks, the full-time fan operation will increase the amount of dirty outside air that infiltrates the ducts and circulates in your home, degrading indoor air quality.
For more information on setting your home's thermostat or upgrading to a cutting-edge programmable thermostat, please contact us at Hartman Heating & Air Conditioning. We provide quality service to the Fort Wayne area.
Our goal is to help educate our customers in New Haven, Indiana and surrounding Fort Wayne area about energy and home comfort issues (specific to HVAC systems). For more information about thermostat fans and other HVAC topics, download our free Home Comfort Resource guide.
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