Once the weather is cooling off, you might be thinking about how you’ll take full advantage of your heating and cooling. After all, HVAC expenses routinely add up to a big piece of your monthly electric bill. To learn new ways to save, some homeowners look closely 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 on during a typical cycle, what will the fan setting provide for an HVAC system? This guide should help. We’ll walk through just what the fan setting is and when you can use it to save money 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 remains on. Some furnaces may continue to operate at a low level with this setting, but in general heating or cooling isn’t being made. The ‘Auto’ setting, on the other hand, 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 whether you do or don’t will depend on your distinct comfort needs.
Advantages to trying the Fan/On setting:
- You can keep the temperature in every room more uniform by allowing the fan to keep running.
- Indoor air quality can increase as constant airflow will keep moving airborne particles through the air filter.
- A smaller number of start-stop cycles for the blower fan helps lengthen its life span. Because the air handler is usually part of the furnace, this means you can prevent the need for furnace repair.
Downsides to using the Fan/On setting:
- A nonstop fan can raise your energy costs slightly.
- Nonstop airflow could 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 will sometimes persist in unfinished spaces like the attic or an attached garage. If you use the fan setting, your HVAC system may pull this warm air into the rest of your home, compelling the HVAC system to work harder to keep up with the desired temperature. In serious heat, this may result in needing AC repair more quickly as wear and tear grows.
The reverse can occur in the winter. Cooler spaces like a basement will hold onto cooler air, which can eventually drift into the rest of your home. Keeping the fan on may pull more cold air upward, increasing the amount of heating you need to keep warm.
If you’re still trying to determine 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 might 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 enhance indoor air quality, helping your family breathe easier.
Your home has hot and cold spots. All kinds of homes wrestle with stubborn hot and cold spots that quickly evolve to a temperature different from the rest of the house. The fan setting might help minimize these changes by constantly refreshing each room’s supply of air.