Once the weather starts to cool off, you may be thinking about how you’ll prepare your heating and cooling. After all, HVAC costs frequently contribute a significant piece of your monthly electric bill. To figure out new ways to save, some homeowners look closer at their thermostat. Is there a setting they could use to improve efficiency?

Most thermostats come with a ‘Fan’ or ‘Fan On’ setting. But if the fan is going during a normal cycle, what can the fan setting provide for the HVAC system? This guide should help. We’ll walk through just what the fan setting is and when you can use it to reduce costs in the summer or winter.

What Is the Fan Setting on My Thermostat?

For the majority of thermostats, the fan setting indicates that the air handler’s blower fan stays on. Some furnaces may continue to run at a low level with 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 shut it off once the cycle is finished.

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

Advantages to switching to the Fan/On setting:

  • You can keep the temperature in each room more consistent by enabling the fan to keep generating airflow.
  • Indoor air quality will be highest since constant airflow will keep passing airborne particles through the air filter.
  • Fewer start-stop cycles for the blower fan helps extend its life span. Since the air handler is usually connected to the furnace, this means you can prevent the need for furnace repair.

Disadvantages to using the Fan/On setting:

  • A continuous fan can increase your energy costs by a small margin.
  • Constant airflow may 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 Each Season

In the summer, warm air can stick around in unfinished spaces like the attic or an attached garage. If you use the fan setting, your HVAC system may draw this warm air into the rest of your home, compelling the HVAC system to work harder to preserve the set temperature. In extreme heat, this can lead to needing AC repair more often as wear and tear gets worse.

The reverse can occur in the winter. Cooler spaces such as a basement will hold onto cooler air, which can eventually drift into the rest of your home. Leaving the fan setting on could pull more cold air upward, increasing the amount of heating you need to keep 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 may be best for you if:

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

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