As the weather begins to cool off, you may be concerned about how you’ll take full advantage of your heating and cooling. After all, HVAC bills frequently add up to a large piece of your monthly electric bill. To learn new ways to lower their HVAC bill, some owners take a closer look at their thermostat. Is there a setting they should use to increase efficiency?

The majority of thermostats include both a ‘Fan’ or ‘Fan On’ setting. But if the fan is running during a typical cycle, what does the fan setting provide for your HVAC system? This guide will help. We’ll review just what 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 bulk of thermostats, the fan setting means that the system's blower fan remains on. Some furnaces will run at a low level in this setting, but in general heating or cooling isn’t being made. The ‘Auto’ setting, on the other hand, will start the fan during a heating or cooling cycle and shut it off once the cycle is finished.

There are pros and cons to using the fan setting on your thermostat, and whether you do or don’t {will|can|should]] depend on your distinct comfort requirements.

Advantages to using the Fan/On setting:

• You can keep the temperature in every room more uniform by enabling the fan to keep generating airflow.
• 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 extend its life span. Because the air handler is typically part of the furnace, this means you can avoid needing furnace repair.

Drawbacks to switching to the Fan/On setting:

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

Should My Thermostat Be on Fan or Auto in Summer/Winter

In the summer, warm air can persist in unfinished spaces such as the attic or an attached garage. If you leave the fan on, your HVAC system may draw this warm air into the rest of your home, pushing the HVAC system to work harder to keep up with the preferred temperature. In extreme heat, this may result in needing AC repair more often as wear and tear increases.

The opposite can occur during the winter. Cooler spaces such as a basement will hold onto cooler air, which will eventually make its way into the rest of your home. Leaving the fan running will sometimes draw more cold air upward, increasing the amount of heating you need to stay 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 will vary. 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 can help to improve indoor air quality, helping your family breathe easier.

Your home deals with hot and cold spots. All kinds of homes wrestle with stubborn hot and cold spots that quickly return to a temperature different from the rest of the house. The fan setting should help lessen these changes by steadily refreshing each room’s supply of air.