Once the weather is cooling off, you might be thinking about how you’ll take full advantage of your heating and cooling. After all, HVAC expenses routinely make up a large chunk of your monthly electric bill. To learn new ways to lower their HVAC bill, some people look closer at their thermostat. Could there be a setting they could use to improve efficiency?

The majority of thermostats include both a ‘Fan’ or ‘Fan On’ setting. But if the fan is on during a regular cycle, what will the fan setting offer for an HVAC system? This guide should help. We’ll review what exactly the fan setting is and when you can use it to reduce costs in the summer or winter.

How Do I Access the Fan Setting on My Thermostat?

For most thermostats, the fan setting means that the system's blower fan stays on. Certain furnaces will generate heat at a low level in this setting, but in most cases heating or cooling isn’t being produced. The ‘Auto’ setting, in contrast, will run the fan over a heating or cooling cycle and shut it off once the cycle is over.

There are pros and cons to switching on the fan setting on your thermostat, and what's ideal {will|can|should]] depend on your unique comfort requirements.

Advantages to switching to the Fan/On setting:

  • You can keep the temperature in every room more consistent by allowing the fan to keep running.
  • Indoor air quality can increase because continuous airflow will keep forcing airborne particles through the air filter.
  • Fewer start-stop cycles for the HVAC fan helps expand its life span. Since the air handler is typically connected to the furnace, this means you might minimize the risk of needing furnace repair.

Drawbacks to using the Fan/On setting:

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

{Choosing Between|Should My Thermostat Be on|Which Setting for My Thermostat? Fan or Auto in Summer/Winter

In the summer, warm air can stick around in unfinished spaces like the attic or an attached garage. If you use the fan setting, your HVAC system can draw this warm air into the rest of your home, pushing the HVAC system to run longer to preserve the set temperature. In serious heat, this could result in needing AC repair more quickly as wear and tear increases.

The reverse can happen in the winter. Cooler spaces such as a basement will hold onto cooler air, which will eventually drift into the rest of your home. Leaving the fan setting on may pump more cold air upward, increasing the amount of heating you need to stay warm.

If you’re still trying to decide if you should switch to the fan/on setting, don’t forget that every home and family’s comfort needs are different. Leaving the HVAC system’s fan on might 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 improve indoor air quality, helping your family breathe easier.

Your home has hot and cold spots. Many homes wrestle with persistent hot and cold spots that quickly shift to a temperature different from the rest of the house. The fan setting should help minimize these changes by consistently refreshing each room’s supply of air.