When the weather is cooling off, you might be wondering about how you’ll prepare your heating and cooling. After all, HVAC bills can contribute a large chunk of your monthly electric bill. To try and find ways to reduce costs, some owners look closely at their thermostat. Could there be a setting they can use to increase efficiency?

Most thermostats have a ‘Fan’ or ‘Fan On’ setting. But if the fan is on during a regular 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 how you can use it to save money in the summer or winter.

Should I Use My Thermostat's Fan Setting?

For the majority of thermostats, the fan setting indicates that the air handler’s blower fan keeps running. Certain furnaces will operate at a low level with this setting, but in general heating or cooling isn’t being produced. The ‘Auto’ setting, on the other hand, will start the fan through a heating or cooling cycle and turn it off when the cycle is over.

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

Advantages to utilizing the Fan/On setting:

  • You can keep the temperature throughout your home more balanced by enabling the fan to keep circulating air.
  • Indoor air quality should improve since constant airflow will keep forcing airborne particles into the air filter.
  • A smaller number of start-stop cycles for the system's fan helps extend its life span. Since the air handler is often part of the furnace, this means you can avoid needing furnace repair.

Disadvantages to utilizing the Fan/On setting:

  • A constant fan will likely increase your energy bills somewhat.
  • Nonstop airflow could clog your air filter in a shorter amount of time, increasing the frequency you will want to replace it.

{Choosing Between|Should My Thermostat Be on|Which Setting for My Thermostat? Fan or Auto in Summer/Winter

In the summer, warm air will sometimes persist in unfinished spaces like the attic or an attached garage. If you use the fan setting, your HVAC system may draw this warm air into the rest of your home, forcing the HVAC system to run longer to maintain the set temperature. In serious heat, this could lead to needing AC repair more often as wear and tear grows.

The opposite can occur 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 could pump 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, keep in mind that every home and family’s comfort needs are not the same. Leaving the HVAC system’s fan on may be ideal for you if:

Someone in your household has allergies. Allergies and other respiratory conditions can be stressful on the family. Leaving the fan on should help to increase indoor air quality, helping your family breathe easier.

Your home has hot and cold spots. Many homes wrestle with difficult hot and cold spots that quickly shift 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.