As the weather starts to cool off, you may be wondering about how you’ll prepare your heating and cooling. After all, HVAC expenses can contribute a large chunk of your monthly electric bill. To figure out new ways to reduce costs, some owners look closer at their thermostat. Is there a setting they can use to improve efficiency?
Most thermostats come with a ‘Fan’ or ‘Fan On’ setting. But if the fan is running during a normal cycle, what will the fan setting offer for an HVAC system? This guide can help. We’ll review just 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 most thermostats, the fan setting indicates that the system's blower fan remains on. Certain 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 start the fan over a heating or cooling cycle and shut it off when the cycle is complete.
There are pros and cons to switching on the fan setting on your thermostat, and what's ideal should depend on your distinct comfort preferences.
Advantages to trying the Fan/On setting:
- You can keep the temperature throughout your home more uniform by enabling the fan to keep generating airflow.
- Indoor air quality will be highest since continuous airflow will keep forcing airborne particles into the air filter.
- Fewer start-stop cycles for the system's fan helps lengthen its life span. Since the air handler is typically connected to the furnace, this means you could prevent the need for furnace repair.
Downsides to switching to the Fan/On setting:
- A continuous fan will likely increase your energy bills by a small margin.
- Nonstop 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 may stick around in unfinished spaces including the attic or an attached garage. If you leave the fan on, your HVAC system might draw this warm air into the rest of your home, compelling the HVAC system to run longer to keep up with the desired temperature. In serious heat, this can result in needing AC repair more often as wear and tear increases.
The opposite can take place during the winter. Cooler spaces like a basement will hold onto cooler air, which will eventually flow into the rest of your home. Leaving the fan running could pull more cold air upward, increasing the amount of heating you need to remain warm.
If you’re still trying to determine if you should use the fan/on setting, keep in mind that every home and family’s comfort needs are different. Leaving the HVAC system’s fan on might be best for you if:
Someone in your household deals with allergies. Allergies and other respiratory conditions can be hard on the family. Leaving the fan on can help to increase indoor air quality, helping your family breathe easier.
Your home experiences hot and cold spots. All kinds of homes wrestle with persistent hot and cold spots that quickly shift to a temperature different from the rest of the house. The fan setting can help limit these changes by steadily refreshing each room’s airflow.