When the weather starts to cool off, you may be wondering about how you’ll prepare your heating and cooling. After all, HVAC bills frequently add up to a significant chunk of your monthly electric bill. To figure out new ways to reduce costs, some owners take a closer look at their thermostat. Maybe there’s a setting they can use to increase efficiency?
The bulk of thermostats come with a ‘Fan’ or ‘Fan On’ setting. But if the fan is going during a normal cycle, what does the fan setting provide for an HVAC system? This guide can help. We’ll walk through just what the fan setting is and whether you can use it to cut costs over the summer or winter.
What Is the Fan Setting on My Thermostat?
For the majority of thermostats, the fan setting means that the HVAC blower fan stays on. Certain furnaces will run at a low level in this setting, but in most cases heating or cooling isn’t being generated. The ‘Auto’ setting, conversely, will start the fan through a heating or cooling cycle and switch it off when the cycle is complete.
There are pros and cons to using the fan setting on your thermostat, and what's ideal will depend on your distinct comfort preferences.
Advantages to trying the Fan/On setting:
- You can keep the temperature throughout your home more consistent by permitting the fan to keep running.
- Indoor air quality will be highest as steady airflow will keep moving airborne pollutants through the air filter.
- A smaller number of start-stop cycles for the blower fan helps expand its life span. Because the air handler is usually connected to the furnace, this means you might avoid needing furnace repair.
Downsides to switching to the Fan/On setting:
- A constant fan can increase your energy costs by a small margin.
- Constant 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
During the summer, warm air may linger in unfinished spaces like the attic or an attached garage. If you use the fan setting, your HVAC system can pull this warm air into the rest of your home, compelling the HVAC system to run longer to preserve the preferred temperature. In serious heat, this could result in needing AC repair more often as wear and tear grows.
The reverse can take place in the winter. Cooler spaces like a basement will hold onto cooler air, which will eventually drift into the rest of your home. Leaving the fan setting on could pump more cold air upward, increasing the amount of heating you need to stay warm.
If you’re still trying to decide if you should use the fan/on setting, remember that every home and family’s comfort needs will vary. Leaving the HVAC system’s fan on could be best for you if:
Someone in your household deals with allergies. Allergies and similar 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 deals with hot and cold spots. Many 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.