When 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 expenses can make up a large portion of your monthly electric bill. To try and find ways to reduce costs, some owners take a closer look at their thermostat. Is there a setting they can use to improve efficiency?

The bulk of thermostats have 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 should help. We’ll share just what the fan setting is and whether you can use it to save money over the summer or winter.

What Is the Fan Setting on My Thermostat?

For most thermostats, the fan setting signifies that the air handler’s blower fan stays on. A few furnaces will operate at a low level in this setting, but for the most part heating or cooling isn’t being made. The ‘Auto’ setting, on the other hand, will turn on the fan during a heating or cooling cycle and turn it off once the cycle is finished.

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

Advantages to using 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 steady airflow will keep moving airborne contaminants into the air filter.
  • A smaller number of start-stop cycles for the HVAC fan helps expand its life span. Because the air handler is typically a component of the furnace, this means you could avoid needing furnace repair.

Drawbacks to utilizing the Fan/On setting:

  • A nonstop fan can add to your energy bills by a small margin.
  • Nonstop airflow could clog your air filter in a shorter amount of time, increasing the frequency you will want to replace it.

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

During the summer, warm air may linger in unfinished spaces such as the attic or an attached garage. If you leave the fan on, your HVAC system might draw this warm air into the rest of your home, forcing the HVAC system to work harder to preserve the set temperature. In serious heat, this may lead to needing AC repair more regularly as wear and tear grows.

The reverse can occur over the winter. Cooler spaces such as a basement will hold onto cooler air, which will eventually drift into the rest of your home. Leaving the fan setting on could draw more cold air upward, increasing the amount of heating you need to remain warm.

If you’re still trying to determine if you should use 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 may be best for you if:

Someone in your household suffers from allergies. Allergies and similar respiratory conditions can be stressful 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. Lots of homes deal with stubborn 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 consistently refreshing each room’s airflow.