When the weather starts to cool off, you may be concerned about how you’ll make the most of your heating and cooling. After all, HVAC expenses can contribute a big chunk of your monthly electric bill. To figure out new ways to lower their HVAC bill, some homeowners take a closer look at their thermostat. Maybe there’s a setting they can use to improve efficiency?

Most thermostats include both a ‘Fan’ or ‘Fan On’ setting. But if the fan is running during a normal cycle, what does the fan setting offer for an HVAC system? This guide should help. We’ll walk through what exactly the fan setting is and when you can use it to save money during 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 stays on. A few furnaces may continue to generate heat at a low level in this setting, but for the most part heating or cooling isn’t being made. The ‘Auto’ setting, in contrast, will start the fan during a heating or cooling cycle and switch it off after the cycle is over.

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

Advantages to switching to the Fan/On setting:

  • You can keep the temperature throughout your home more consistent by enabling the fan to keep generating airflow.
  • Indoor air quality will be highest because steady airflow will keep forcing airborne contaminants through the air filter.
  • A smaller amount of start-stop cycles for the system’s fan helps extend its life span. Because the air handler is often a component of the furnace, this means you might avoid needing furnace repair.

Drawbacks to using the Fan/On setting:

  • A nonstop fan could add to your energy bills by a small margin.
  • Continuous airflow may clog your air filter up more quickly, increasing the frequency you’ll need to replace it.

{Choosing Between|Should My Thermostat Be on|Which Setting for My Thermostat? Fan or Auto in Each Season

During the summer, warm air may persist in unfinished spaces such as the attic or an attached garage. If you use the fan setting, your HVAC system can gradually move this warm air into the rest of your home, compelling the HVAC system to run longer to maintain the desired temperature. In severe heat, this can lead to needing AC repair more quickly as wear and tear increases.

The opposite can happen during the winter. Cooler spaces like a basement will hold onto cooler air, which can eventually make its way into the rest of your home. Leaving the fan running will sometimes draw more cold air upward, increasing the amount of heating you need to stay warm.

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

Someone in your household suffers from 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. All kinds of homes wrestle with difficult hot and cold spots that quickly evolve to a temperature different from the rest of the house. The fan setting should help limit these changes by steadily refreshing each room’s airflow.