Once the weather starts to cool off, you may be concerned about how you’ll take full advantage of your heating and cooling. After all, HVAC bills frequently add up to a significant chunk of your monthly electric bill. To try and find ways to save, some people take a closer look at their thermostat. Maybe there’s a setting they can use to improve efficiency?

The bulk of thermostats include both a ‘Fan’ or ‘Fan On’ setting. But if the fan is on during a normal cycle, what will the fan setting provide for an HVAC system? This guide will help. We’ll review what exactly the fan setting is and whether you can use it to cut costs over the summer or winter.

Should I Use My Thermostat’s Fan Setting?

For the bulk of thermostats, the fan setting indicates that the air handler’s blower fan stays on. Some furnaces may continue to operate at a low level in this setting, but in general 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 turn it off after the cycle is complete.

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

Advantages to using the Fan/On setting:

  • You can keep the temperature throughout your home more consistent by enabling the fan to keep circulating air.
  • Indoor air quality will be highest since steady airflow will keep moving airborne particles into the air filter.
  • A smaller number of start-stop cycles for the blower fan helps extend its life span. Because the air handler is usually part of the furnace, this means you could prevent the need for furnace repair.

Drawbacks to switching to the Fan/On setting:

  • A nonstop fan will likely increase your energy expenses slightly.
  • Continuous airflow could clog your air filter up more quickly, 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 stick around in unfinished spaces including the attic or an attached garage. If you keep the fan running, your HVAC system can gradually move this warm air into the rest of your home, forcing the HVAC system to work more to maintain the preferred temperature. In extreme heat, this could lead to needing AC repair more quickly as wear and tear increases.

The reverse can occur over the winter. Cooler spaces such as a basement will hold onto cooler air, which will eventually flow into the rest of your home. Leaving the fan running may pump more cold air upward, increasing the amount of heating you need to keep 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 different. Leaving the HVAC system’s fan on might be ideal for you if:

Someone in your household deals with allergies. Allergies and other respiratory conditions can be hard on the family. Leaving the fan on should help to increase indoor air quality, helping your family breathe easier.

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