As the weather begins to cool off, you may be wondering about how you’ll take full advantage of your heating and cooling. After all, HVAC costs frequently contribute a big chunk of your monthly electric bill. To figure out new ways to lower their HVAC bill, some owners take a closer look at their thermostat. Is there a setting they should use to improve efficiency?

The majority of thermostats have a ‘Fan’ or ‘Fan On’ setting. But if the fan is on during a regular cycle, what will the fan setting provide for an HVAC system? This guide will help. We’ll review just what the fan setting is and when you can use it to cut costs in the summer or winter.

What Is the Fan Setting on My Thermostat?

For most thermostats, the fan setting signifies that the air handler’s blower fan remains on. Some furnaces may continue to operate at a low level with this setting, but in general heating or cooling isn’t being generated. The ‘Auto’ setting, in contrast, will run the fan during a heating or cooling cycle and switch it off after the cycle is complete.

There are pros and cons to switching on the fan setting on your thermostat, and whether you do or don’t {will|can|should]] depend on your unique comfort preferences.

Advantages to utilizing the Fan/On setting:

  • You can keep the temperature in every room more balanced by enabling the fan to keep circulating air.
  • Indoor air quality can increase because constant airflow will keep passing airborne contaminants through the air filter.
  • Fewer start-stop cycles for the system's fan helps lengthen its life span. Since the air handler is usually a component of the furnace, this means you could prevent the need for furnace repair.

Disadvantages to switching to the Fan/On setting:

  • A nonstop fan could add to your energy costs somewhat.
  • Constant airflow can clog your air filter in a shorter amount of time, increasing the frequency you will want to replace it.

Should My Thermostat Be on Fan or Auto in Summer/Winter

In the summer, warm air may stick around in unfinished spaces like the attic or an attached garage. If you keep the fan running, your HVAC system can pull this warm air into the rest of your home, pushing the HVAC system to run longer to keep up with the desired temperature. In extreme heat, this may result in needing AC repair more regularly as wear and tear increases.

The opposite can occur during 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. Keeping the fan on could pump more cold air upward, increasing the amount of heating you need to stay warm.

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

Someone in your household suffers from allergies. Allergies and similar respiratory conditions can be tough 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. Lots of 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 limit these changes by steadily refreshing each room’s supply of air.