When the weather begins to cool off, you are probably concerned about how you’ll take full advantage of your heating and cooling. After all, HVAC bills frequently add up to a big chunk of your monthly electric bill. To learn new ways to reduce costs, some owners take a closer look 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 does the fan setting offer for the HVAC system? This guide will help. We’ll walk through what exactly the fan setting is and when you can use it to reduce costs over the summer or winter.
What Is the Fan Setting on My Thermostat?
For the majority of thermostats, the fan setting indicates that the air handler’s blower fan stays on. A few furnaces may continue to operate at a low level in this setting, but for the most part heating or cooling isn’t being produced. The ‘Auto’ setting, in contrast, will turn on the fan during a heating or cooling cycle and turn it off when the cycle is finished.
There are advantages and disadvantages to switching on the fan setting on your thermostat, and whether you do or don’t will depend on your unique comfort requirements.
Advantages to trying the Fan/On setting:
- You can keep the temperature throughout your home more consistent by allowing the fan to keep running.
- Indoor air quality will be highest since constant airflow will keep forcing airborne pollutants into the air filter.
- A smaller number of start-stop cycles for the system's fan helps expand its life span. As the air handler is usually connected to the furnace, this means you might prevent the need for furnace repair.
Downsides to switching to the Fan/On setting:
- A nonstop fan can add to your energy costs somewhat.
- Continuous airflow could clog your air filter soon, increasing the frequency you should replace it.
Should My Thermostat Be on Fan or Auto in Summer/Winter
Through the summer, warm air may stick around in unfinished spaces like the attic or an attached garage. If you keep the fan running, your HVAC system may pull this warm air into the rest of your home, pushing the HVAC system to work more to preserve the preferred temperature. In serious heat, this may lead to needing AC repair more often as wear and tear gets worse.
The reverse can take place over the winter. Cooler spaces such as a basement will hold onto cooler air, which may eventually drift into the rest of your home. Leaving the fan running may pull more cold air upward, increasing the amount of heating you need to keep warm.
If you’re still trying to decide if you should use the fan/on setting, don’t forget that every home and family’s comfort needs are different. Leaving the HVAC system’s fan on could be best 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 deals with hot and cold spots. Lots 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 can help lessen these changes by consistently refreshing each room’s supply of air.