As the weather begins to cool off, you may be wondering about how you’ll make the most of your heating and cooling. After all, HVAC costs can add up to a large portion of your monthly electric bill. To learn new ways to save, some homeowners look closely at their thermostat. Is there a setting they should use to increase efficiency?

The majority of thermostats have a ‘Fan’ or ‘Fan On’ setting. But if the fan is running during a typical cycle, what does the fan setting offer for your HVAC system? This guide will help. We’ll review just what the fan setting is and when you can use it to save money during the summer or winter.

How Do I Access the Fan Setting on My Thermostat?

For the majority of thermostats, the fan setting means that the system’s blower fan keeps running. A few furnaces can operate at a low level in this setting, but in most cases heating or cooling isn’t being generated. The ‘Auto’ setting, in contrast, will run the fan through a heating or cooling cycle and turn it off when the cycle is over.

There are advantages and disadvantages to using the fan setting on your thermostat, and whether you do or don’t {will|can|should]] depend on your unique comfort needs.

Advantages to switching to the Fan/On setting:

  • You can keep the temperature throughout your home more consistent by enabling the fan to keep generating airflow.
  • Indoor air quality will be highest as continuous airflow will keep forcing airborne particles into the air filter.
  • A smaller amount of start-stop cycles for the blower fan helps extend its life span. As the air handler is often part of the furnace, this means you can prevent the need for furnace repair.

Drawbacks to utilizing the Fan/On setting:

  • A constant fan will likely increase your energy bills somewhat.
  • Constant 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

In the summer, warm air will sometimes linger in unfinished spaces including the attic or an attached garage. If you keep the fan running, your HVAC system can draw this warm air into the rest of your home, compelling the HVAC system to run longer to maintain the set temperature. In serious heat, this could lead to needing AC repair more often as wear and tear grows.

The reverse can occur during the winter. Cooler spaces like a basement will hold onto cooler air, which may eventually make its way into the rest of your home. Keeping the fan on may pump more cold air upward, increasing the amount of heating you need to keep warm.

If you’re still trying to determine if you should switch to the fan/on setting, keep in mind that every home and family’s comfort needs are different. Leaving the HVAC system’s fan on could work for you if:

Someone in your household deals with allergies. Allergies and other 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 has hot and cold spots. Many homes wrestle with difficult hot and cold spots that quickly evolve to a temperature different from the rest of the house. The fan setting should help limit these changes by constantly refreshing each room’s supply of air.