As the weather starts to cool off, you are probably thinking about how you’ll take full advantage of your heating and cooling. After all, HVAC costs frequently contribute a big portion of your monthly electric bill. To learn new ways to reduce costs, some owners take a closer look at their thermostat. Is there a setting they should use to improve efficiency?

The majority of thermostats include both 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 can help. We’ll share what exactly the fan setting is and how you can use it to save money over the summer or winter.

What Is the Fan Setting on My Thermostat?

For most thermostats, the fan setting signifies that the system's blower fan stays on. Certain furnaces can run at a low level with this setting, but in most cases heating or cooling isn’t being made. The ‘Auto’ setting, on the other hand, will turn on the fan over a heating or cooling cycle and switch it off once the cycle is finished.

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

Advantages to trying the Fan/On setting:

  • You can keep the temperature in every room more uniform by enabling the fan to keep circulating air.
  • Indoor air quality should improve since continuous airflow will keep moving airborne pollutants through the air filter.
  • Fewer start-stop cycles for the HVAC fan helps lengthen its life span. Because the air handler is usually a component of the furnace, this means you can avoid needing furnace repair.

Downsides to using the Fan/On setting:

  • A constant fan will likely raise your energy costs slightly.
  • Constant airflow may clog your air filter up more quickly, increasing the frequency you’ll need to replace it.

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

In 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 more to maintain the desired temperature. In severe heat, this may lead to needing AC repair more often as wear and tear increases.

The opposite can take place 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 may pump more cold air upward, increasing the amount of heating you need to stay warm.

If you’re still trying to determine 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 may be best for you if:

Someone in your household suffers from allergies. Allergies and other respiratory conditions can be stressful 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. Lots 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 minimize these changes by consistently refreshing each room’s airflow.