Once the weather is cooling off, you may be concerned about how you’ll prepare your heating and cooling. After all, HVAC costs frequently make up a significant piece of your monthly electric bill. To learn new ways to lower their HVAC bill, some owners take a closer look at their thermostat. Is there a setting they could use to boost efficiency?

Most thermostats come with a ‘Fan’ or ‘Fan On’ setting. But if the fan is going during a normal cycle, what will the fan setting provide for the HVAC system? This guide should help. We’ll walk through just what the fan setting is and when 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 can operate at a low level with this setting, but in most cases heating or cooling isn’t being produced. The ‘Auto’ setting, on the other hand, will run the fan over a heating or cooling cycle and switch it off after the cycle is over.

There are benefits and drawbacks to switching on the fan setting on your thermostat, and the ideal option {will|can|should]] depend on your personal comfort preferences.

Advantages to trying the Fan/On setting:

  • You can keep the temperature in every room more uniform by allowing the fan to keep running.
  • Indoor air quality will be highest because steady airflow will keep forcing airborne particles through the air filter.
  • A smaller number of start-stop cycles for the system’s fan helps lengthen its life span. Since the air handler is typically a component of the furnace, this means you could minimize the risk of needing furnace repair.

Drawbacks to switching to the Fan/On setting:

  • A nonstop fan can increase your energy expenses slightly.
  • Continuous airflow could clog your air filter up more quickly, increasing the frequency you should replace it.

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

During the summer, warm air can persist in unfinished spaces like the attic or an attached garage. If you leave the fan on, your HVAC system may gradually move this warm air into the rest of your home, pushing the HVAC system to work harder to keep up with the set temperature. In serious heat, this can result in needing AC repair more quickly as wear and tear gets worse.

The opposite can happen in the winter. Cooler spaces like a basement will hold onto cooler air, which will eventually drift into the rest of your home. Keeping the fan on could 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 use the fan/on setting, keep in mind that every home and family’s comfort needs are not the same. Leaving the HVAC system’s fan on might be best 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 improve indoor air quality, helping your family breathe easier.

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