Once the weather starts to cool off, you might be wondering about how you’ll make the most of your heating and cooling. After all, HVAC bills routinely make up a large piece of your monthly electric bill. To learn new ways to reduce costs, some homeowners look closely at their thermostat. Could there be a setting they can use to improve efficiency?

Most thermostats have a ‘Fan’ or ‘Fan On’ setting. But if the fan is running during a regular cycle, what can the fan setting offer for an HVAC system? This guide will help. We’ll share precisely what the fan setting is and when you can use it to save money in the summer or winter.

What Is the Fan Setting on My Thermostat?

For the majority of thermostats, the fan setting indicates that the HVAC blower fan stays on. A few furnaces will run at a low level in this setting, but in most cases heating or cooling isn’t being made. The ‘Auto’ setting, conversely, will turn on the fan during a heating or cooling cycle and shut it off when the cycle is over.

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

Advantages to trying the Fan/On setting:

  • You can keep the temperature throughout your home more consistent by permitting the fan to keep circulating air.
  • Indoor air quality will be highest because steady airflow will keep passing airborne contaminants into the air filter.
  • A smaller number of start-stop cycles for the blower fan helps expand its life span. As the air handler is usually part of the furnace, this means you can minimize the risk of needing furnace repair.

Downsides to utilizing the Fan/On setting:

  • A nonstop fan will likely raise your energy costs slightly.
  • Constant airflow may 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

Through the summer, warm air will sometimes persist in unfinished spaces including the attic or an attached garage. If you use the fan setting, your HVAC system can pull this warm air into the rest of your home, pushing the HVAC system to work harder to maintain the set temperature. In serious heat, this could lead to needing AC repair more regularly as wear and tear grows.

The reverse can take place over the winter. Cooler spaces like a basement will hold onto cooler air, which will eventually flow into the rest of your home. Leaving the fan setting on will sometimes pump more cold air upward, increasing the amount of heating you need to stay warm.

If you’re still trying to decide if you should switch to 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 ideal 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 should help to improve 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 can help lessen these changes by steadily refreshing each room’s airflow.