Once the weather begins to cool off, you might be thinking about how you’ll prepare your heating and cooling. After all, HVAC bills can contribute a big chunk of your monthly electric bill. To try and find ways to lower their HVAC bill, some homeowners look closer at their thermostat. Is there a setting they could use to boost efficiency?
The majority of thermostats include both a ‘Fan’ or ‘Fan On’ setting. But if the fan is going during a normal cycle, what will the fan setting offer for the HVAC system? This guide can help. We’ll share precisely what the fan setting is and whether you can use it to reduce costs during the summer or winter.
What Is the Fan Setting on My Thermostat?
For the majority of thermostats, the fan setting signifies that the system's blower fan stays on. Certain furnaces will run at a low level in this setting, but for the most part heating or cooling isn’t being made. The ‘Auto’ setting, in contrast, will start the fan during a heating or cooling cycle and shut it off after the cycle is finished.
There are benefits and drawbacks to switching on the fan setting on your thermostat, and what's ideal should depend on your unique comfort requirements.
Advantages to switching to the Fan/On setting:
- You can keep the temperature in every room more uniform by enabling the fan to keep circulating air.
- Indoor air quality will be highest as steady airflow will keep forcing airborne contaminants through the air filter.
- A smaller amount of start-stop cycles for the blower fan helps expand its life span. Since the air handler is typically a component of the furnace, this means you could prevent the need for furnace repair.
Drawbacks to using the Fan/On setting:
- A continuous fan can raise your energy costs somewhat.
- Constant airflow may clog your air filter in a shorter amount of time, increasing the frequency you’ll need to replace it.
Should My Thermostat Be on Fan or Auto in Summer/Winter
Through the summer, warm air will sometimes persist in unfinished spaces such as the attic or an attached garage. If you keep the fan running, your HVAC system might pull this warm air into the rest of your home, forcing the HVAC system to run longer to preserve the preferred temperature. In serious heat, this may lead to needing AC repair more often as wear and tear grows.
The reverse can happen during the winter. Cooler spaces such as a basement will hold onto cooler air, which can eventually flow into the rest of your home. Leaving the fan setting on will sometimes 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 may be ideal for you if:
Someone in your household has allergies. Allergies and other respiratory conditions can be hard on the family. Leaving the fan on can help 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 should help limit these changes by consistently refreshing each room’s ventilation.