As the weather starts to cool off, you are probably wondering about how you’ll take full advantage of your heating and cooling. After all, HVAC expenses routinely make up a significant piece of your monthly electric bill. To figure out new ways to lower their HVAC bill, some homeowners look closer at their thermostat. Is there a setting they should use to improve efficiency?

Most thermostats have a ‘Fan’ or ‘Fan On’ setting. But if the fan is on during a normal cycle, what does the fan setting offer for the HVAC system? This guide will help. We’ll review precisely 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 the majority of thermostats, the fan setting indicates that the HVAC blower fan stays on. A few furnaces may continue to generate heat at a low level in this setting, but in most cases heating or cooling isn’t being made. The ‘Auto’ setting, in contrast, will turn on the fan during a heating or cooling cycle and switch it off after the cycle is complete.

There are advantages and disadvantages to using the fan setting on your thermostat, and whether you do or don’t {will|can|should]] depend on your unique comfort requirements.

Advantages to trying the Fan/On setting:

  • You can keep the temperature throughout your home more consistent by allowing the fan to keep circulating air.
  • Indoor air quality will be highest since steady airflow will keep passing airborne particles through the air filter.
  • A smaller amount of start-stop cycles for the system's fan helps lengthen its life span. Because the air handler is usually part of the furnace, this means you can minimize the risk of needing furnace repair.

Drawbacks to utilizing the Fan/On setting:

  • A nonstop fan can raise your energy expenses somewhat.
  • Continuous 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 will sometimes stick around in unfinished spaces such as the attic or an attached garage. If you keep the fan running, your HVAC system can gradually move this warm air into the rest of your home, pushing the HVAC system to work harder to keep up with the preferred temperature. In severe heat, this can result in needing AC repair more regularly as wear and tear grows.

The reverse can take place over the winter. Cooler spaces such as a basement will hold onto cooler air, which can eventually make its way into the rest of your home. Leaving the fan running will sometimes draw more cold air upward, increasing the amount of heating you need to remain warm.

If you’re still trying to decide if you should try the fan/on setting, don’t forget that every home and family’s comfort needs will vary. Leaving the HVAC system’s fan on might be ideal for you if:

Someone in your household suffers from 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 deals with hot and cold spots. Lots of homes deal with stubborn hot and cold spots that quickly evolve to a temperature different from the rest of the house. The fan setting should help limit these changes by constantly refreshing each room’s ventilation.