When the weather starts to cool off, you might be wondering about how you’ll prepare your heating and cooling. After all, HVAC costs can contribute a significant piece of your monthly electric bill. To try and find ways to save, some homeowners look closely at their thermostat. Is there a setting they can use to increase efficiency?
Most thermostats include both a ‘Fan’ or ‘Fan On’ setting. But if the fan is going during a regular cycle, what does the fan setting offer for the HVAC system? This guide can help. We’ll walk through what exactly the fan setting is and how you can use it to cut costs over the summer or winter.
What Is the Fan Setting on My Thermostat?
For most thermostats, the fan setting means that the system's blower fan remains on. Certain furnaces can operate at a low level in this setting, but for the most part heating or cooling isn’t being produced. The ‘Auto’ setting, conversely, will run the fan through a heating or cooling cycle and turn it off after the cycle is finished.
There are advantages and disadvantages to using the fan setting on your thermostat, and the ideal option should depend on your unique comfort requirements.
Advantages to switching to the Fan/On setting:
- You can keep the temperature throughout your home more consistent by enabling the fan to keep circulating air.
- Indoor air quality should improve because constant airflow will keep forcing airborne particles through the air filter.
- A smaller number of start-stop cycles for the blower fan helps extend its life span. As the air handler is typically part of the furnace, this means you could avoid needing furnace repair.
Disadvantages to switching to the Fan/On setting:
- A nonstop fan will likely raise your energy costs by a small margin.
- 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
During the summer, warm air will sometimes stick around in unfinished spaces including the attic or an attached garage. If you keep the fan running, your HVAC system can pull this warm air into the rest of your home, compelling the HVAC system to run longer to keep up with the preferred temperature. In severe heat, this can result in needing AC repair more quickly as wear and tear gets worse.
The opposite can happen during the winter. Cooler spaces such as a basement will hold onto cooler air, which will eventually drift into the rest of your home. Leaving the fan running could 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, keep in mind 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 suffers from allergies. Allergies and other respiratory conditions can be stressful on the family. Leaving the fan on can help to increase indoor air quality, helping your family breathe easier.
Your home experiences hot and cold spots. Lots of homes deal with persistent hot and cold spots that quickly return to a temperature different from the rest of the house. The fan setting should help limit these changes by consistently refreshing each room’s airflow.