When the weather starts to cool off, you might be thinking about how you’ll prepare your heating and cooling. After all, HVAC costs can contribute a big chunk of your monthly electric bill. To learn new ways to save, some people look closer at their thermostat. Is there a setting they should use to improve efficiency?

The majority of thermostats come with a ‘Fan’ or ‘Fan On’ setting. But if the fan is going during a normal cycle, what does the fan setting offer for an HVAC system? This guide should help. We’ll share what exactly the fan setting is and how you can use it to save money over the summer or winter.

My Thermostat Has a Fan Setting?

For most thermostats, the fan setting signifies that the HVAC blower fan keeps running. Certain furnaces may continue to generate heat at a low level in this setting, but in general heating or cooling isn’t being generated. The ‘Auto’ setting, in contrast, will run the fan through a heating or cooling cycle and turn it off when the cycle is complete.

There are advantages and disadvantages to trying the fan setting on your thermostat, and whether you do or don’t {will|can|should]] depend on your personal comfort needs.

Advantages to switching to the Fan/On setting:

  • You can keep the temperature in each room more balanced by permitting the fan to keep generating airflow.
  • Indoor air quality will be highest since steady airflow will keep passing airborne contaminants through the air filter.
  • A smaller number of start-stop cycles for the system’s fan helps lengthen its life span. As the air handler is often a component of the furnace, this means you can minimize the risk of needing furnace repair.

Disadvantages to using the Fan/On setting:

  • A continuous fan could add to your energy expenses somewhat.
  • Continuous 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

In the summer, warm air may stick around in unfinished spaces including 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, forcing the HVAC system to run longer to preserve the preferred temperature. In serious heat, this can result in needing AC repair more regularly as wear and tear increases.

The opposite can occur over the winter. Cooler spaces such as a basement will hold onto cooler air, which can eventually flow into the rest of your home. Leaving the fan running may pump more cold air upward, increasing the amount of heating you need to remain warm.

If you’re still trying to determine if you should use the fan/on setting, don’t forget that every home and family’s comfort needs will vary. Leaving the HVAC system’s fan on may be ideal for you if:

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

Your home experiences hot and cold spots. All kinds of homes deal with difficult hot and cold spots that quickly return to a temperature different from the rest of the house. The fan setting should help limit these changes by steadily refreshing each room’s supply of air.