Once the weather is cooling off, you might be concerned about how you’ll take full advantage of your heating and cooling. After all, HVAC expenses routinely contribute a big chunk of your monthly electric bill. To learn new ways to lower their HVAC bill, some owners look closely at their thermostat. Maybe there’s a setting they should use to improve efficiency?

Most thermostats come with a ‘Fan’ or ‘Fan On’ setting. But if the fan is going 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 how you can use it to save money over the summer or winter.

How Do I Access the Fan Setting on My Thermostat?

For the bulk of thermostats, the fan setting means that the air handler’s blower fan stays on. A few furnaces can operate at a low level with this setting, but for the most part heating or cooling isn’t being generated. The ‘Auto’ setting, in contrast, will turn on the fan during a heating or cooling cycle and shut it off once the cycle is finished.

There are benefits and drawbacks to using the fan setting on your thermostat, and what’s ideal {will|can|should]] depend on your unique comfort requirements.

Advantages to utilizing the Fan/On setting:

  • You can keep the temperature throughout your home more balanced by permitting the fan to keep running.
  • Indoor air quality will be highest as continuous airflow will keep passing airborne contaminants into the air filter.
  • Fewer start-stop cycles for the system’s fan helps expand its life span. Since the air handler is usually connected to the furnace, this means you might minimize the risk of needing furnace repair.

Downsides to switching to the Fan/On setting:

  • A constant fan will likely increase your energy expenses slightly.
  • Continuous airflow can clog your air filter soon, increasing the frequency you should replace it.

Which Setting for My Thermostat? Fan or Auto in Summer/Winter

In the summer, warm air can linger in unfinished spaces including the attic or an attached garage. If you leave the fan on, your HVAC system can pull this warm air into the rest of your home, forcing the HVAC system to run longer to preserve the set temperature. In extreme heat, this can lead to needing AC repair more regularly as wear and tear grows.

The opposite can happen over the winter. Cooler spaces like a basement will hold onto cooler air, which will eventually drift into the rest of your home. Keeping the fan on will sometimes 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 use the fan/on setting, keep in mind that every home and family’s comfort needs will vary. Leaving the HVAC system’s fan on could be ideal for you if:

Someone in your household suffers from allergies. Allergies and other respiratory conditions can be stressful on the family. Leaving the fan on should help to enhance indoor air quality, helping your family breathe easier.

Your home experiences hot and cold spots. Many homes deal with difficult 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 constantly refreshing each room’s supply of air.