Once the weather is cooling off, you may be concerned about how you’ll take full advantage of your heating and cooling. After all, HVAC bills routinely contribute a significant chunk of your monthly electric bill. To figure out new ways to save, some people take a closer look at their thermostat. Maybe there’s a setting they should use to increase efficiency?
The majority of thermostats have a ‘Fan’ or ‘Fan On’ setting. But if the fan is on during a normal cycle, what will the fan setting provide for an HVAC system? This guide should help. We’ll share precisely what the fan setting is and how you can use it to reduce costs during the summer or winter.
What Is the Fan Setting on My Thermostat?
For most thermostats, the fan setting signifies that the air handler’s blower fan stays on. Some furnaces will run at a low level in this setting, but in most cases heating or cooling isn’t being produced. The ‘Auto’ setting, on the other hand, will start the fan through a heating or cooling cycle and turn it off when the cycle is finished.
There are benefits and drawbacks to trying the fan setting on your thermostat, and whether you do or don’t will depend on your unique comfort preferences.
Advantages to trying the Fan/On setting:
- You can keep the temperature throughout your home more consistent by enabling the fan to keep generating airflow.
- Indoor air quality can increase since continuous airflow will keep moving airborne particles into the air filter.
- Fewer start-stop cycles for the system's fan helps expand its life span. As the air handler is typically part of the furnace, this means you can prevent the need for furnace repair.
Downsides to using the Fan/On setting:
- A constant fan will likely increase your energy bills somewhat.
- Nonstop airflow may 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 can persist in unfinished spaces like the attic or an attached garage. If you leave the fan on, your HVAC system may gradually move this warm air into the rest of your home, compelling the HVAC system to run longer to preserve the desired temperature. In extreme heat, this can result in needing AC repair more regularly as wear and tear increases.
The opposite can occur during the winter. Cooler spaces such as a basement will hold onto cooler air, which may eventually make its way into the rest of your home. Keeping the fan on could pump more cold air upward, increasing the amount of heating you need to keep warm.
If you’re still trying to decide if you should switch to 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 suffers from allergies. Allergies and similar respiratory conditions can be tough on the family. Leaving the fan on is more likely to increase indoor air quality, helping your family breathe easier.
Your home deals with hot and cold spots. Many homes deal with persistent hot and cold spots that quickly evolve to a temperature different from the rest of the house. The fan setting might help limit these changes by steadily refreshing each room’s supply of air.