As the weather is cooling off, you are probably concerned about how you’ll prepare your heating and cooling. After all, HVAC expenses frequently make up a significant portion of your monthly electric bill. To try and find ways to save, some owners look closer at their thermostat. Is there a setting they can use to improve efficiency?
The bulk of thermostats come with a ‘Fan’ or ‘Fan On’ setting. But if the fan is running during a regular cycle, what does the fan setting provide for your HVAC system? This guide should help. We’ll review what exactly the fan setting is and when you can use it to cut costs over the summer or winter.
What Is the Fan Setting on My Thermostat?
For the bulk of thermostats, the fan setting signifies that the air handler’s blower fan keeps running. A few furnaces may continue to run at a low level with this setting, but for the most part heating or cooling isn’t being produced. The ‘Auto’ setting, in contrast, will run the fan through a heating or cooling cycle and switch it off when the cycle is finished.
There are pros and cons to switching on the fan setting on your thermostat, and the ideal option will depend on your personal comfort preferences.
Advantages to trying the Fan/On setting:
- You can keep the temperature in every room more uniform by enabling the fan to keep generating airflow.
- Indoor air quality can increase since continuous airflow will keep moving airborne contaminants into the air filter.
- A smaller amount of start-stop cycles for the system's fan helps extend its life span. As the air handler is typically part of the furnace, this means you might minimize the risk of needing furnace repair.
Disadvantages to using the Fan/On setting:
- A constant fan can add to your energy costs slightly.
- Continuous airflow can 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 may persist in unfinished spaces such as the attic or an attached garage. If you use the fan setting, your HVAC system can draw this warm air into the rest of your home, pushing the HVAC system to run longer to preserve the preferred temperature. In extreme heat, this can result in needing AC repair more often as wear and tear gets worse.
The reverse can take place in the winter. Cooler spaces like a basement will hold onto cooler air, which will eventually make its way 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 stay warm.
If you’re still trying to determine if you should switch to 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 best 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 improve indoor air quality, helping your family breathe easier.
Your home has hot and cold spots. Lots of homes deal with stubborn hot and cold spots that quickly return to a temperature different from the rest of the house. The fan setting should help minimize these changes by steadily refreshing each room’s airflow.