When the weather is cooling off, you might be wondering about how you’ll take full advantage of your heating and cooling. After all, HVAC costs can make up a big piece of your monthly electric bill. To learn new ways to lower their HVAC bill, some homeowners look closer at their thermostat. Could there be a setting they should use to improve efficiency?

The majority of thermostats have a ‘Fan’ or ‘Fan On’ setting. But if the fan is running during a typical cycle, what can the fan setting offer for your HVAC system? This guide can help. We’ll review just what the fan setting is and whether you can use it to cut costs during the summer or winter.

My Thermostat Has a Fan Setting?

For the majority of thermostats, the fan setting means that the air handler’s blower fan keeps running. Some furnaces may continue to operate at a low level in this setting, but in most cases heating or cooling isn’t being produced. The ‘Auto’ setting, conversely, will turn on the fan through a heating or cooling cycle and turn it off after the cycle is over.

There are pros and cons to using the fan setting on your thermostat, and what's ideal {will|can|should]] depend on your personal comfort needs.

Advantages to switching to the Fan/On setting:

  • You can keep the temperature throughout your home more balanced by allowing the fan to keep circulating air.
  • Indoor air quality can increase since continuous airflow will keep forcing airborne pollutants through the air filter.
  • Fewer start-stop cycles for the HVAC fan helps expand its life span. Because the air handler is usually part of the furnace, this means you might avoid needing furnace repair.

Drawbacks to switching to the Fan/On setting:

  • A nonstop fan will likely raise your energy bills slightly.
  • Constant airflow could clog your air filter soon, increasing the frequency you’ll need to replace it.

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

Through the summer, warm air can stick around in unfinished spaces like the attic or an attached garage. If you keep the fan running, your HVAC system can pull 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 may lead to needing AC repair more quickly as wear and tear grows.

The reverse can happen 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 setting on may draw 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, remember that every home and family’s comfort needs will vary. Leaving the HVAC system’s fan on might 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 improve indoor air quality, helping your family breathe easier.

Your home experiences hot and cold spots. Many homes wrestle with persistent hot and cold spots that quickly evolve to a temperature different from the rest of the house. The fan setting can help minimize these changes by constantly refreshing each room’s supply of air.