Once the weather begins to cool off, you may be thinking about how you’ll make the most of your heating and cooling. After all, HVAC bills can make up a significant chunk of your monthly electric bill. To try and find ways to lower their HVAC bill, some homeowners look closely at their thermostat. Could there be a setting they could use to increase efficiency?

Most thermostats have a ‘Fan’ or ‘Fan On’ setting. But if the fan is running during a typical cycle, what does the fan setting provide for the HVAC system? This guide can help. We’ll share what exactly the fan setting is and whether you can use it to cut costs during the summer or winter.

What Is the Fan Setting on My Thermostat?

For the majority of thermostats, the fan setting means that the system’s blower fan stays on. Certain furnaces will run at a low level with this setting, but for the most part heating or cooling isn’t being made. The ‘Auto’ setting, in contrast, will run the fan through a heating or cooling cycle and switch it off when the cycle is over.

There are pros and cons to trying the fan setting on your thermostat, and what’s ideal {will|can|should]] depend on your distinct comfort needs.

Advantages to using the Fan/On setting:

  • You can keep the temperature in each room more balanced by enabling the fan to keep circulating air.
  • Indoor air quality will be highest because continuous airflow will keep moving airborne contaminants into the air filter.
  • A smaller number of start-stop cycles for the system’s fan helps extend its life span. Because the air handler is usually a component of the furnace, this means you could avoid needing furnace repair.

Downsides to switching to the Fan/On setting:

  • A nonstop fan will likely raise your energy costs by a small margin.
  • Continuous airflow could clog your air filter up more quickly, increasing the frequency you’ll need to replace it.

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

Through 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 maintain the set temperature. In severe heat, this could result in needing AC repair more quickly as wear and tear gets worse.

The opposite can take place over the winter. Cooler spaces like a basement will hold onto cooler air, which will eventually flow into the rest of your home. Keeping the fan on could pump 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 switch to the fan/on setting, remember that every home and family’s comfort needs are different. 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 tough on the family. Leaving the fan on is more likely to increase indoor air quality, helping your family breathe easier.

Your home experiences hot and cold spots. Lots of homes deal with difficult hot and cold spots that quickly return to a temperature different from the rest of the house. The fan setting can help lessen these changes by consistently refreshing each room’s ventilation.