As the weather begins to cool off, you are probably concerned about how you’ll prepare your heating and cooling. After all, HVAC bills can contribute a big piece of your monthly electric bill. To try and find ways to save, some people take a closer look at their thermostat. Maybe there’s a setting they can use to improve efficiency?

The bulk of thermostats include both a ‘Fan’ or ‘Fan On’ setting. But if the fan is going during a typical cycle, what does the fan setting provide for the HVAC system? This guide should help. We’ll review just what the fan setting is and how you can use it to reduce costs over the summer or winter.

My Thermostat Has a Fan Setting?

For most thermostats, the fan setting indicates that the HVAC blower fan keeps running. Certain furnaces will generate heat at a low level in this setting, but in general heating or cooling isn’t being produced. The ‘Auto’ setting, conversely, will run the fan over a heating or cooling cycle and switch it off after the cycle is complete.

There are benefits and drawbacks to trying the fan setting on your thermostat, and what’s ideal {will|can|should]] depend on your personal comfort requirements.

Advantages to switching to the Fan/On setting:

  • You can keep the temperature throughout your home more consistent by allowing the fan to keep generating airflow.
  • Indoor air quality can increase as constant airflow will keep forcing airborne contaminants through the air filter.
  • A smaller amount of start-stop cycles for the HVAC fan helps extend its life span. As the air handler is typically connected to the furnace, this means you might prevent the need for furnace repair.

Drawbacks to using the Fan/On setting:

  • A continuous fan can raise your energy costs slightly.
  • Continuous airflow could clog your air filter up more quickly, increasing the frequency you should replace it.

Should My Thermostat Be on? Fan or Auto in Summer/Winter

During the summer, warm air may persist in unfinished spaces including the attic or an attached garage. If you keep the fan running, your HVAC system can pull this warm air into the rest of your home, pushing the HVAC system to work more to preserve the preferred temperature. In serious heat, this can lead to needing AC repair more regularly as wear and tear increases.

The reverse can take place during the winter. Cooler spaces such as a basement will hold onto cooler air, which may eventually flow into the rest of your home. Leaving the fan setting on could pump more cold air upward, increasing the amount of heating you need to keep warm.

If you’re still trying to determine if you should use the fan/on setting, remember that every home and family’s comfort needs are different. Leaving the HVAC system’s fan on may be best for you if:

Someone in your household suffers from allergies. Allergies and other respiratory conditions can be hard on the family. Leaving the fan on should help to enhance indoor air quality, helping your family breathe easier.

Your home experiences hot and cold spots. All kinds of homes wrestle with stubborn hot and cold spots that quickly shift to a temperature different from the rest of the house. The fan setting can help limit these changes by constantly refreshing each room’s supply of air.