Once the weather begins to cool off, you might be concerned about how you’ll prepare your heating and cooling. After all, HVAC costs can add up to a significant portion of your monthly electric bill. To try and find ways to reduce costs, some owners look closely at their thermostat. Could there be a setting they can use to improve efficiency?

Most thermostats include both a ‘Fan’ or ‘Fan On’ setting. But if the fan is going during a regular cycle, what can the fan setting offer for an HVAC system? This guide should help. We’ll walk through precisely what the fan setting is and how you can use it to cut costs over the summer or winter.

My Thermostat Has a Fan Setting?

For most thermostats, the fan setting means that the system's blower fan keeps running. Certain furnaces will operate at a low level with this setting, but in general heating or cooling isn’t being made. The ‘Auto’ setting, conversely, will turn on the fan over a heating or cooling cycle and shut it off once the cycle is finished.

There are pros and cons to trying the fan setting on your thermostat, and what's ideal {will|can|should]] depend on your personal comfort preferences.

Advantages to using the Fan/On setting:

  • You can keep the temperature throughout your home more uniform by permitting the fan to keep circulating air.
  • Indoor air quality can increase because constant airflow will keep passing airborne pollutants through the air filter.
  • Fewer start-stop cycles for the blower fan helps lengthen its life span. Since the air handler is often a component of the furnace, this means you can avoid needing furnace repair.

Disadvantages to using the Fan/On setting:

  • A continuous fan can increase your energy expenses somewhat.
  • Constant airflow could clog your air filter up more quickly, increasing the frequency you should replace it.

{Choosing Between|Should My Thermostat Be on|Which Setting for My Thermostat? Fan or Auto in Summer/Winter

Through the summer, warm air will sometimes stick around in unfinished spaces such as the attic or an attached garage. If you leave the fan on, your HVAC system may gradually move this warm air into the rest of your home, pushing the HVAC system to run longer to keep up with the set temperature. In extreme heat, this could result in needing AC repair more often as wear and tear gets worse.

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

If you’re still trying to figure out if you should try the fan/on setting, don’t forget that every home and family’s comfort needs are different. Leaving the HVAC system’s fan on could work for you if:

Someone in your household has allergies. Allergies and similar respiratory conditions can be stressful on the family. Leaving the fan on should help to improve indoor air quality, helping your family breathe easier.

Your home deals with hot and cold spots. Many homes wrestle with stubborn hot and cold spots that quickly evolve to a temperature different from the rest of the house. The fan setting can help minimize these changes by steadily refreshing each room’s supply of air.