Once the weather starts to cool off, you might be thinking about how you’ll make the most of your heating and cooling. After all, HVAC costs frequently make up a big chunk of your monthly electric bill. To learn new ways to lower their HVAC bill, some homeowners look closely at their thermostat. Maybe there’s a setting they should use to increase efficiency?

Most thermostats include both a ‘Fan’ or ‘Fan On’ setting. But if the fan is going during a normal cycle, what can the fan setting provide for the HVAC system? This guide should help. We’ll review precisely what the fan setting is and whether you can use it to reduce costs during the summer or winter.

What Is the Fan Setting on My Thermostat?

For the bulk of thermostats, the fan setting signifies that the air handler’s blower fan remains on. Some furnaces may continue to run at a low level in this setting, but for the most part heating or cooling isn’t being generated. The ‘Auto’ setting, conversely, will start the fan over a heating or cooling cycle and switch it off once the cycle is finished.

There are advantages and disadvantages to using the fan setting on your thermostat, and whether you do or don’t {will|can|should]] depend on your unique comfort requirements.

Advantages to using the Fan/On setting:

  • You can keep the temperature throughout your home more uniform by permitting the fan to keep circulating air.
  • Indoor air quality will be highest as constant airflow will keep forcing airborne particles through the air filter.
  • A smaller amount of start-stop cycles for the blower fan helps expand its life span. Because the air handler is typically part of the furnace, this means you might prevent the need for furnace repair.

Disadvantages to utilizing the Fan/On setting:

  • A constant fan will likely add to your energy bills by a small margin.
  • Nonstop airflow could clog your air filter up more quickly, increasing the frequency you will want to replace it.

{Choosing Between|Should My Thermostat Be on|Which Setting for My Thermostat? Fan or Auto in Each Season

In the summer, warm air may persist in unfinished spaces including the attic or an attached garage. If you use the fan setting, your HVAC system might gradually move this warm air into the rest of your home, forcing the HVAC system to run longer to preserve the set temperature. In extreme heat, this may lead to needing AC repair more regularly as wear and tear gets worse.

The opposite can occur in the winter. Cooler spaces like a basement will hold onto cooler air, which may 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 stay 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 could be best for you if:

Someone in your household has allergies. Allergies and similar respiratory conditions can be hard on the family. Leaving the fan on is more likely to increase indoor air quality, helping your family breathe easier.

Your home deals with hot and cold spots. All kinds of homes wrestle with persistent hot and cold spots that quickly evolve to a temperature different from the rest of the house. The fan setting might help lessen these changes by consistently refreshing each room’s supply of air.