As the weather begins to cool off, you are probably concerned about how you’ll make the most of your heating and cooling. After all, HVAC expenses frequently add up to a large piece of your monthly electric bill. To figure out new ways to reduce costs, some homeowners take a closer look at their thermostat. Maybe there’s a setting they could use to boost efficiency?

The majority of thermostats include both a ‘Fan’ or ‘Fan On’ setting. But if the fan is going during a normal cycle, what will the fan setting provide for the HVAC system? This guide can help. We’ll review what exactly the fan setting is and whether you can use it to cut costs over 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 general heating or cooling isn’t being made. The ‘Auto’ setting, in contrast, will turn on the fan over a heating or cooling cycle and switch it off after the cycle is complete.

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

Advantages to using the Fan/On setting:

  • You can keep the temperature in every room more balanced by enabling the fan to keep circulating air.
  • Indoor air quality can increase since steady airflow will keep moving airborne contaminants through the air filter.
  • A smaller number of start-stop cycles for the HVAC fan helps lengthen its life span. Because the air handler is typically connected to the furnace, this means you might prevent the need for furnace repair.

Drawbacks to switching to the Fan/On setting:

  • A nonstop fan could raise your energy bills 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

In the summer, warm air will sometimes linger in unfinished spaces like the attic or an attached garage. If you keep the fan running, your HVAC system may draw this warm air into the rest of your home, compelling the HVAC system to work harder to maintain the preferred temperature. In serious heat, this could lead to needing AC repair more regularly as wear and tear increases.

The reverse can occur in the winter. Cooler spaces such as a basement will hold onto cooler air, which may eventually flow into the rest of your home. Keeping the fan on may draw more cold air upward, increasing the amount of heating you need to stay warm.

If you’re still trying to figure out if you should try 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 other respiratory conditions can be tough on the family. Leaving the fan on can help to increase indoor air quality, helping your family breathe easier.

Your home has hot and cold spots. Lots 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 limit these changes by steadily refreshing each room’s ventilation.