Setting Your Thermostat: Fan On or Auto?

Whether you have a standard digital or manual thermostat, or a more advanced programmable or WiFi thermostat, you may have wondered about the fan setting. The “cool” and “heat” settings are obvious, but deciding upon the best fan settings — “on” and “auto” — takes a little more thought. Read on to learn how setting your thermostat fan to “on” or “auto” affects comfort, efficiency and indoor air quality.

Fan “On” or “Auto”: What’s the Difference?

The thermostat settings “cool” and “heat” control the cooling and heating systems and home temperature. The fan settings “on” and “auto” control the operation of the blower after the cooling and heating systems turn off.

Setting the thermostat fan mode to “on” will make the blower run continuously after the cooling or heating system has turned off. “Auto” fan mode turns the blower on and off in time with the cooling and heating systems.

Better Comfort and Efficiency

Running the fan continuously in the “on” setting doesn’t affect comfort very much, unless you just like to hear the HVAC system running. Using ceiling fans in occupied rooms to promote airflow is more practical and uses less energy, so if you want to keep energy bills in check, setting the thermostat fan mode to “auto” is best.

Additionally, by running the blower continuously after the cooling cycle ends, water condensation on the evaporator coil evaporates and returns back to the living spaces to increase indoor humidity.

Better Indoor Air Quality

Indoor air quality is an important element of home comfort and health. Many homeowners don’t realize that the indoor air quality of the average home is two to five times more polluted than outdoor air. Using the “on” setting for continuous airflow helps boost indoor air quality by running airflow through the furnace filter more times.

However, you may still face higher energy bills. The best solution for saving energy and maintaining healthful indoor air quality is a whole-house air purifier.

For more tips on setting your thermostat for the best results, contact Roth Home & Cooling today. We’ve helped Portland area homeowners with HVAC solutions since 1976.