Once the weather is cooling off, you may be concerned about how you’ll take full advantage of your heating and cooling. After all, HVAC costs frequently contribute a significant chunk of your monthly electric bill. To try and find ways to save, some owners look closely at their thermostat. Could there be a setting they can use to boost efficiency?

Most thermostats have a ‘Fan’ or ‘Fan On’ setting. But if the fan is running during a typical cycle, what does the fan setting provide for the HVAC system? This guide should help. We’ll review what exactly the fan setting is and how you can use it to cut costs over the summer or winter.

What Is the Fan Setting on My Thermostat?

For the bulk of thermostats, the fan setting indicates that the system’s blower fan keeps running. Some furnaces may continue to operate at a low level in this setting, but in most cases heating or cooling isn’t being made. The ‘Auto’ setting, in contrast, will turn on the fan during a heating or cooling cycle and turn it off when the cycle is over.

There are advantages and disadvantages to trying the fan setting on your thermostat, and the ideal option {will|can|should]] depend on your unique comfort preferences.

Advantages to trying the Fan/On setting:

  • You can keep the temperature in every room more balanced by allowing the fan to keep circulating air.
  • Indoor air quality can increase because steady airflow will keep moving airborne particles through the air filter.
  • A smaller amount of start-stop cycles for the system’s fan helps expand its life span. Since the air handler is typically a component of the furnace, this means you might minimize the risk of needing furnace repair.

Disadvantages to using the Fan/On setting:

  • A continuous fan can increase your energy expenses slightly.
  • Constant airflow could clog your air filter in a shorter amount of time, increasing the frequency you should replace it.

Which Setting for My Thermostat? Fan or Auto in Summer/Winter

Through the summer, warm air will sometimes persist in unfinished spaces such as the attic or an attached garage. If you use the fan setting, your HVAC system might draw this warm air into the rest of your home, forcing the HVAC system to work more to preserve the desired temperature. In extreme heat, this may lead to needing AC repair more regularly as wear and tear gets worse.

The reverse can take place over the winter. Cooler spaces such as a basement will hold onto cooler air, which will eventually make its way into the rest of your home. Leaving the fan setting on will sometimes draw 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 use 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 be best for you if:

Someone in your household has allergies. Allergies and other respiratory conditions can be tough on the family. Leaving the fan on is more likely to improve indoor air quality, helping your family breathe easier.

Your home has hot and cold spots. Lots of homes wrestle with persistent hot and cold spots that quickly shift to a temperature different from the rest of the house. The fan setting should help lessen these changes by consistently refreshing each room’s supply of air.