As the weather begins to cool off, you are probably concerned about how you’ll make the most of your heating and cooling. After all, HVAC bills frequently make up a large chunk of your monthly electric bill. To learn new ways to save, some owners take a closer look at their thermostat. Maybe there’s a setting they can use to boost efficiency?

The bulk of thermostats have a ‘Fan’ or ‘Fan On’ setting. But if the fan is on during a typical cycle, what can the fan setting offer for your HVAC system? This guide will help. We’ll share what exactly the fan setting is and when 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 means that the HVAC blower fan stays on. A few furnaces will generate heat at a low level in this setting, but for the most part heating or cooling isn’t being made. The ‘Auto’ setting, on the other hand, will start the fan during a heating or cooling cycle and shut it off after the cycle is over.

There are pros and cons 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 trying 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 can increase as constant airflow will keep passing airborne contaminants through the air filter.
  • A smaller number of start-stop cycles for the system's fan helps extend its life span. Since the air handler is often a component of the furnace, this means you could avoid needing furnace repair.

Downsides to utilizing the Fan/On setting:

  • A continuous fan will likely raise your energy expenses by a small margin.
  • Nonstop airflow may clog your air filter soon, increasing the frequency you should replace it.

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

During the summer, warm air can linger in unfinished spaces like the attic or an attached garage. If you use the fan setting, your HVAC system might gradually move this warm air into the rest of your home, forcing the HVAC system to work more to maintain the desired temperature. In serious heat, this could lead to needing AC repair more often as wear and tear increases.

The reverse can take place during the winter. Cooler spaces like a basement will hold onto cooler air, which will eventually flow into the rest of your home. Leaving the fan setting on will sometimes 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, remember that every home and family’s comfort needs will vary. Leaving the HVAC system’s fan on might be ideal for you if:

Someone in your household has 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 has hot and cold spots. Many homes deal with persistent hot and cold spots that quickly evolve to a temperature different from the rest of the house. The fan setting can help limit these changes by consistently refreshing each room’s supply of air.