Once the weather is cooling off, you might be concerned about how you’ll prepare your heating and cooling. After all, HVAC bills can make up a significant piece of your monthly electric bill. To try and find ways to save, some owners take a closer look at their thermostat. Is there a setting they could use to increase efficiency?

The majority of thermostats have a ‘Fan’ or ‘Fan On’ setting. But if the fan is on during a typical cycle, what can the fan setting provide for your HVAC system? This guide can help. We’ll walk through just what the fan setting is and whether 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 means that the system’s blower fan keeps running. A few furnaces can generate heat at a low level in this setting, but in most cases heating or cooling isn’t being produced. The ‘Auto’ setting, conversely, will turn on the fan over a heating or cooling cycle and shut it off when the cycle is over.

There are advantages and disadvantages 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 switching to the Fan/On setting:

  • You can keep the temperature throughout your home more balanced by permitting the fan to keep running.
  • Indoor air quality can increase because constant airflow will keep moving airborne pollutants through the air filter.
  • Fewer start-stop cycles for the system’s fan helps extend its life span. Because the air handler is often a component of the furnace, this means you can avoid needing furnace repair.

Downsides to switching to the Fan/On setting:

  • A nonstop fan could raise your energy costs somewhat.
  • Continuous 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 Each Season

In the summer, warm air can linger in unfinished spaces including the attic or an attached garage. If you leave the fan on, your HVAC system might gradually move this warm air into the rest of your home, pushing the HVAC system to work more to maintain the preferred temperature. In serious heat, this can lead to needing AC repair more quickly as wear and tear grows.

The reverse can take place in 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. Leaving the fan setting on may 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 switch to the fan/on setting, remember 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 has allergies. Allergies and other respiratory conditions can be hard on the family. Leaving the fan on can help to increase indoor air quality, helping your family breathe easier.

Your home experiences hot and cold spots. All kinds of homes wrestle with stubborn 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 constantly refreshing each room’s ventilation.