Once the weather begins to cool off, you are probably thinking about how you’ll make the most of your heating and cooling. After all, HVAC bills routinely make up a significant portion of your monthly electric bill. To learn new ways to save, some owners look closely at their thermostat. Could there be a setting they could use to improve efficiency?
Most thermostats have a ‘Fan’ or ‘Fan On’ setting. But if the fan is running during a typical cycle, what will the fan setting provide for your HVAC system? This guide should 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 most thermostats, the fan setting means that the HVAC blower fan remains on. A few furnaces can operate at a low level with this setting, but in most cases heating or cooling isn’t being produced. The ‘Auto’ setting, in contrast, will run the fan through a heating or cooling cycle and turn it off when the cycle is complete.
There are advantages and disadvantages to using the fan setting on your thermostat, and the ideal option should depend on your personal comfort requirements.
Advantages to using the Fan/On setting:
- You can keep the temperature throughout your home more uniform by enabling the fan to keep circulating air.
- Indoor air quality will be highest since constant airflow will keep forcing airborne contaminants into the air filter.
- Fewer start-stop cycles for the blower fan helps lengthen its life span. Since the air handler is usually connected to the furnace, this means you can prevent the need for furnace repair.
Downsides to using the Fan/On setting:
- A continuous fan will likely increase your energy costs somewhat.
- 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 will sometimes linger 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, forcing the HVAC system to work harder to maintain the preferred temperature. In severe heat, this may result in needing AC repair more regularly as wear and tear increases.
The reverse can occur during the winter. Cooler spaces such as a basement will hold onto cooler air, which can eventually drift into the rest of your home. Leaving the fan setting on will sometimes draw more cold air upward, increasing the amount of heating you need to keep warm.
If you’re still trying to figure out if you should use 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 deals with 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 has hot and cold spots. Lots of homes wrestle with persistent hot and cold spots that quickly return to a temperature different from the rest of the house. The fan setting should help lessen these changes by steadily refreshing each room’s supply of air.