Once the weather begins to cool off, you are probably wondering about how you’ll prepare your heating and cooling. After all, HVAC bills can make up a big piece of your monthly electric bill. To figure out new ways to reduce costs, some owners look closer at their thermostat. Is there a setting they could use to improve efficiency?

Most thermostats come with a ‘Fan’ or ‘Fan On’ setting. But if the fan is on during a typical cycle, what can the fan setting offer for the HVAC system? This guide should help. We’ll review just what the fan setting is and when you can use it to cut costs over the summer or winter.

What Is the Fan Setting on My Thermostat?

For most thermostats, the fan setting means that the air handler’s blower fan remains on. Some furnaces can generate heat at a low level with this setting, but for the most part heating or cooling isn’t being generated. The ‘Auto’ setting, conversely, will run the fan through a heating or cooling cycle and turn it off after the cycle is complete.

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

Advantages to trying the Fan/On setting:

  • You can keep the temperature in each room more consistent by enabling the fan to keep circulating air.
  • Indoor air quality can increase because continuous airflow will keep moving airborne particles into the air filter.
  • A smaller number of start-stop cycles for the blower fan helps extend its life span. As the air handler is often part of the furnace, this means you might avoid needing furnace repair.

Downsides to utilizing the Fan/On setting:

  • A continuous fan could increase your energy expenses slightly.
  • Continuous airflow could clog your air filter up more quickly, 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 use the fan setting, your HVAC system might draw this warm air into the rest of your home, pushing the HVAC system to work more to keep up with the desired temperature. In serious heat, this may lead to needing AC repair more often as wear and tear grows.

The reverse can happen in the winter. Cooler spaces like a basement will hold onto cooler air, which can eventually make its way into the rest of your home. Leaving the fan running may pump more cold air upward, increasing the amount of heating you need to stay warm.

If you’re still trying to determine if you should use the fan/on setting, remember 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 hard 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 stubborn 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 airflow.