As the weather begins to cool off, you may be concerned about how you’ll make the most of your heating and cooling. After all, HVAC expenses routinely contribute a significant piece of your monthly electric bill. To figure out new ways to lower their HVAC bill, some homeowners take a closer look at their thermostat. Could there be a setting they should use to boost efficiency?

The majority of thermostats come with a ‘Fan’ or ‘Fan On’ setting. But if the fan is on during a normal cycle, what will the fan setting provide for the HVAC system? This guide will help. We’ll walk through what exactly the fan setting is and when you can use it to save money in the summer or winter.

Should I Use My Thermostat’s Fan Setting?

For most thermostats, the fan setting indicates that the air handler’s blower fan keeps running. Some furnaces will operate at a low level in this setting, but for the most part heating or cooling isn’t being generated. The ‘Auto’ setting, on the other hand, will run the fan over a heating or cooling cycle and shut it off once the cycle is finished.

There are advantages and disadvantages to trying the fan setting on your thermostat, and the ideal option {will|can|should]] depend on your unique comfort needs.

Advantages to utilizing the Fan/On setting:

  • You can keep the temperature in every room more consistent by allowing the fan to keep circulating air.
  • Indoor air quality can increase as continuous airflow will keep moving airborne particles through the air filter.
  • A smaller amount of start-stop cycles for the blower fan helps lengthen its life span. As the air handler is usually connected to the furnace, this means you might prevent the need for furnace repair.

Drawbacks to using the Fan/On setting:

  • A nonstop fan can increase your energy costs somewhat.
  • Continuous airflow can clog your air filter soon, increasing the frequency you will want to replace it.

Which Setting for My Thermostat? Fan or Auto in Each Season

In the summer, warm air may linger in unfinished spaces like the attic or an attached garage. If you leave the fan on, your HVAC system can pull this warm air into the rest of your home, forcing the HVAC system to work more to keep up with the desired temperature. In extreme heat, this may result in needing AC repair more quickly as wear and tear increases.

The reverse can occur in the winter. Cooler spaces like a basement will hold onto cooler air, which may eventually flow into the rest of your home. Leaving the fan running may 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 try 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 may 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 should help to improve indoor air quality, helping your family breathe easier.

Your home experiences hot and cold spots. Lots of homes wrestle 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.