As the weather starts to cool off, you may be thinking about how you’ll take full advantage of your heating and cooling. After all, HVAC costs routinely add up to a big chunk of your monthly electric bill. To learn new ways to lower their HVAC bill, some people take a closer look at their thermostat. Maybe there’s a setting they could use to boost efficiency?
Most thermostats come with a ‘Fan’ or ‘Fan On’ setting. But if the fan is running during a typical cycle, what can the fan setting provide for the HVAC system? This guide will help. We’ll review just what the fan setting is and when you can use it to save money over the summer or winter.
What Is the Fan Setting on My Thermostat?
For most thermostats, the fan setting indicates that the system's blower fan keeps running. Certain furnaces can run 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 during a heating or cooling cycle and shut it off after the cycle is complete.
There are advantages and disadvantages to switching on the fan setting on your thermostat, and what's ideal can depend on your distinct comfort preferences.
Advantages to using the Fan/On setting:
- You can keep the temperature in every room more balanced by enabling the fan to keep circulating air.
- Indoor air quality should improve because continuous airflow will keep passing airborne particles into the air filter.
- A smaller amount of start-stop cycles for the system's fan helps expand its life span. Since the air handler is typically part of the furnace, this means you could prevent the need for furnace repair.
Drawbacks to using the Fan/On setting:
- A constant fan could add to your energy bills by a small margin.
- Nonstop airflow can clog your air filter soon, increasing the frequency you should replace it.
Should My Thermostat Be on Fan or Auto in Summer/Winter
In the summer, warm air can persist in unfinished spaces including the attic or an attached garage. If you use the fan setting, your HVAC system can gradually move this warm air into the rest of your home, pushing the HVAC system to work more to maintain the preferred temperature. In extreme heat, this could result in needing AC repair more quickly as wear and tear increases.
The reverse can take place during the winter. Cooler spaces such as a basement will hold onto cooler air, which can eventually flow into the rest of your home. Keeping the fan on will sometimes draw more cold air upward, increasing the amount of heating you need to stay warm.
If you’re still trying to decide if you should try the fan/on setting, remember that every home and family’s comfort needs are not the same. Leaving the HVAC system’s fan on may work for you if:
Someone in your household has allergies. Allergies and similar respiratory conditions can be hard on the family. Leaving the fan on is more likely to improve indoor air quality, helping your family breathe easier.
Your home experiences hot and cold spots. Lots of homes deal with stubborn hot and cold spots that quickly shift to a temperature different from the rest of the house. The fan setting might help limit these changes by consistently refreshing each room’s supply of air.