Once the weather is cooling off, you may be concerned about how you’ll make the most of your heating and cooling. After all, HVAC costs can contribute a significant portion of your monthly electric bill. To figure out new ways to reduce costs, some people look closer at their thermostat. Maybe there’s a setting they can use to improve efficiency?

The bulk of thermostats come with a ‘Fan’ or ‘Fan On’ setting. But if the fan is going during a typical cycle, what can the fan setting provide for the HVAC system? This guide will help. We’ll review just what the fan setting is and whether you can use it to save money in the summer or winter.

How Do I Access the Fan Setting on My Thermostat?

For the majority of thermostats, the fan setting means that the HVAC blower fan stays on. Certain furnaces will operate at a low level with this setting, but in general heating or cooling isn’t being made. The ‘Auto’ setting, in contrast, will start the fan during a heating or cooling cycle and switch it off when the cycle is complete.

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

Advantages to switching to the Fan/On setting:

  • You can keep the temperature throughout your home more uniform by enabling the fan to keep generating airflow.
  • Indoor air quality will be highest because constant airflow will keep forcing airborne contaminants through 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.

Disadvantages to switching to the Fan/On setting:

  • A constant fan could add to your energy expenses somewhat.
  • Constant airflow could clog your air filter up more quickly, increasing the frequency you’ll need to replace it.

Which Setting for My Thermostat? Fan or Auto in Summer/Winter

Through the summer, warm air will sometimes persist in unfinished spaces like the attic or an attached garage. If you keep the fan running, your HVAC system might draw this warm air into the rest of your home, forcing the HVAC system to run longer to keep up with the desired temperature. In serious heat, this can lead to needing AC repair more regularly as wear and tear increases.

The opposite can occur over the winter. Cooler spaces such as a basement will hold onto cooler air, which can eventually flow into the rest of your home. Leaving the fan running will sometimes draw more cold air upward, increasing the amount of heating you need to stay warm.

If you’re still trying to determine 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 could work for you if:

Someone in your household deals with allergies. Allergies and similar respiratory conditions can be stressful on the family. Leaving the fan on is more likely to enhance 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 might help limit these changes by steadily refreshing each room’s airflow.