When the weather starts to cool off, you might be thinking about how you’ll take full advantage of your heating and cooling. After all, HVAC costs can make up a big portion of your monthly electric bill. To try and find ways to save, some owners take a closer look at their thermostat. Is there a setting they should use to improve efficiency?

The majority of thermostats include both a ‘Fan’ or ‘Fan On’ setting. But if the fan is on during a regular cycle, what can the fan setting offer for your HVAC system? This guide can help. We’ll review just 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 most thermostats, the fan setting means that the HVAC blower fan stays on. A few furnaces may continue to run at a low level with this setting, but in most cases heating or cooling isn’t being made. The ‘Auto’ setting, on the other hand, will run the fan over a heating or cooling cycle and switch it off after the cycle is complete.

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

Advantages to trying the Fan/On setting:

• You can keep the temperature throughout your home more uniform by permitting the fan to keep circulating air.
• Indoor air quality should improve since continuous airflow will keep forcing airborne contaminants into the air filter.
• A smaller number of start-stop cycles for the blower fan helps lengthen its life span. As the air handler is typically connected to the furnace, this means you could minimize the risk of needing furnace repair.

Drawbacks to using the Fan/On setting:

• A constant fan will likely raise your energy bills somewhat.
• Continuous airflow may clog your air filter up more quickly, increasing the frequency you should replace it.

Should My Thermostat Be on Fan or Auto in Summer/Winter

Through the summer, warm air may persist 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 harder to maintain the preferred temperature. In severe heat, this can lead to needing AC repair more quickly as wear and tear gets worse.

The opposite can take place in the winter. Cooler spaces like a basement will hold onto cooler air, which may eventually drift into the rest of your home. Leaving the fan setting on may pump more cold air upward, increasing the amount of heating you need to keep 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 different. Leaving the HVAC system’s fan on could work for you if:

Someone in your household deals with allergies. Allergies and other 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 deal with stubborn hot and cold spots that quickly shift to a temperature different from the rest of the house. The fan setting might help lessen these changes by steadily refreshing each room’s airflow.