When the weather is cooling off, you might be concerned about how you’ll make the most of your heating and cooling. After all, HVAC expenses routinely add up to a large piece of your monthly electric bill. To figure out new ways to save, some homeowners take a closer look at their thermostat. Could there be a setting they could use to boost 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 provide for the HVAC system? This guide can help. We’ll share just what the fan setting is and how you can use it to save money in the summer or winter.

What Is the Fan Setting on My Thermostat?

For most thermostats, the fan setting means that the HVAC blower fan keeps running. Some furnaces can generate heat at a low level with this setting, but for the most part heating or cooling isn’t being made. The ‘Auto’ setting, on the other hand, will run the fan over a heating or cooling cycle and switch it off when the cycle is finished.

There are benefits and drawbacks to trying the fan setting on your thermostat, and what's ideal {will|can|should]] depend on your personal comfort needs.

Advantages to utilizing the Fan/On setting:

  • You can keep the temperature in every room more uniform by permitting the fan to keep running.
  • Indoor air quality will be highest as steady airflow will keep passing airborne particles into the air filter.
  • A smaller amount of start-stop cycles for the HVAC fan helps extend its life span. As the air handler is often a component of the furnace, this means you could avoid needing furnace repair.

Downsides to using the Fan/On setting:

  • A constant fan could add to your energy expenses somewhat.
  • Constant airflow may clog your air filter soon, increasing the frequency you’ll need to replace it.

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

During the summer, warm air can persist in unfinished spaces including the attic or an attached garage. If you keep the fan running, your HVAC system can draw this warm air into the rest of your home, compelling the HVAC system to work harder to preserve the preferred temperature. In severe heat, this could result in needing AC repair more regularly as wear and tear gets worse.

The opposite can happen during the winter. Cooler spaces like a basement will hold onto cooler air, which can eventually drift 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 stay warm.

If you’re still trying to decide if you should switch to the fan/on setting, don’t forget that every home and family’s comfort needs are not the same. Leaving the HVAC system’s fan on could work for you if:

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

Your home deals with hot and cold spots. All kinds of homes wrestle 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 consistently refreshing each room’s airflow.