When the weather is cooling off, you are probably thinking about how you’ll take full advantage of your heating and cooling. After all, HVAC costs routinely make up a significant piece of your monthly electric bill. To try and find ways to save, some owners look closely at their thermostat. Maybe there’s a setting they should use to boost efficiency?

The bulk of thermostats come with a ‘Fan’ or ‘Fan On’ setting. But if the fan is running 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 whether you can use it to reduce costs in the summer or winter.

Should I Use My Thermostat’s Fan Setting?

For most thermostats, the fan setting means that the air handler’s blower fan remains on. A few furnaces can generate heat at a low level in this setting, but in general heating or cooling isn’t being produced. The ‘Auto’ setting, conversely, will start the fan during a heating or cooling cycle and turn it off when the cycle is complete.

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

Advantages to trying the Fan/On setting:

  • You can keep the temperature throughout your home more uniform by allowing the fan to keep running.
  • Indoor air quality can increase because continuous airflow will keep passing airborne particles into the air filter.
  • A smaller amount of start-stop cycles for the system’s fan helps extend its life span. Since the air handler is often connected to the furnace, this means you could minimize the risk of needing furnace repair.

Drawbacks to switching to the Fan/On setting:

  • A constant fan will likely raise your energy bills by a small margin.
  • Constant airflow can clog your air filter soon, increasing the frequency you should replace it.

{Choosing Between|Should My Thermostat Be on|Which Setting for My Thermostat? Fan or Auto in Summer/Winter

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

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. Keeping the fan on could draw more cold air upward, increasing the amount of heating you need to keep 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 are not the same. Leaving the HVAC system’s fan on might work for you if:

Someone in your household has allergies. Allergies and other respiratory conditions can be stressful on the family. Leaving the fan on can help to enhance indoor air quality, helping your family breathe easier.

Your home experiences hot and cold spots. Lots of homes wrestle with persistent hot and cold spots that quickly evolve to a temperature different from the rest of the house. The fan setting should help lessen these changes by consistently refreshing each room’s ventilation.