As the weather is cooling off, you may be concerned about how you’ll take full advantage of your heating and cooling. After all, HVAC bills routinely contribute a big chunk of your monthly electric bill. To try and find ways to lower their HVAC bill, some people look closer at their thermostat. Maybe there’s 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 running during a typical cycle, what will the fan setting offer for an HVAC system? This guide can help. We’ll share what exactly the fan setting is and whether you can use it to cut costs in the summer or winter.

Should I Use My Thermostat’s Fan Setting?

For the bulk of thermostats, the fan setting signifies that the system’s blower fan remains on. Some furnaces may continue to run at a low level in this setting, but in most cases heating or cooling isn’t being made. The ‘Auto’ setting, on the other hand, will run the fan through a heating or cooling cycle and shut it off when the cycle is complete.

There are pros and cons to switching on the fan setting on your thermostat, and whether you do or don’t {will|can|should]] depend on your personal comfort requirements.

Advantages to using the Fan/On setting:

  • You can keep the temperature throughout your home more consistent by permitting the fan to keep running.
  • Indoor air quality can increase since steady airflow will keep passing airborne particles through the air filter.
  • Fewer start-stop cycles for the blower fan helps expand its life span. Because the air handler is typically a component of the furnace, this means you might prevent the need for furnace repair.

Disadvantages to using the Fan/On setting:

  • A continuous fan could add to your energy expenses somewhat.
  • Nonstop airflow can clog your air filter in a shorter amount of time, increasing the frequency you will want to replace it.

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

During the summer, warm air will sometimes linger in unfinished spaces like the attic or an attached garage. If you use the fan setting, your HVAC system might pull this warm air into the rest of your home, pushing the HVAC system to run longer to maintain the desired temperature. In severe heat, this can lead to needing AC repair more often as wear and tear gets worse.

The opposite can take place over the winter. Cooler spaces like a basement will hold onto cooler air, which can eventually make its way into the rest of your home. Leaving the fan running will sometimes pull more cold air upward, increasing the amount of heating you need to remain 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 might be ideal for you if:

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

Your home has hot and cold spots. Lots of homes wrestle with persistent hot and cold spots that quickly return to a temperature different from the rest of the house. The fan setting can help limit these changes by steadily refreshing each room’s ventilation.