As the weather is cooling off, you might be concerned about how you’ll make the most of your heating and cooling. After all, HVAC bills frequently make up a significant portion of your monthly electric bill. To learn new ways to lower their HVAC bill, some people look closely at their thermostat. Maybe there’s a setting they should use to improve efficiency?

The bulk of thermostats come with a ‘Fan’ or ‘Fan On’ setting. But if the fan is running during a normal cycle, what will the fan setting provide for an HVAC system? This guide will help. We’ll share precisely what the fan setting is and how you can use it to reduce costs over the summer or winter.

What Is the Fan Setting on My Thermostat?

For most thermostats, the fan setting signifies that the system's blower fan remains on. Certain furnaces will operate at a low level with this setting, but for the most part heating or cooling isn’t being made. The ‘Auto’ setting, on the other hand, will turn on the fan through a heating or cooling cycle and shut it off once 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 unique comfort requirements.

Advantages to switching to the Fan/On setting:

  • You can keep the temperature in each room more uniform by enabling the fan to keep running.
  • Indoor air quality should improve as constant airflow will keep moving airborne pollutants through the air filter.
  • Fewer start-stop cycles for the system's fan helps expand its life span. Because the air handler is often connected to the furnace, this means you can avoid needing furnace repair.

Disadvantages to using the Fan/On setting:

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

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

During the summer, warm air can persist in unfinished spaces such as the attic or an attached garage. If you keep the fan running, your HVAC system may draw this warm air into the rest of your home, pushing the HVAC system to work more to preserve the preferred temperature. In severe heat, this can lead to needing AC repair more quickly as wear and tear gets worse.

The reverse can take place over the winter. Cooler spaces such as a basement will hold onto cooler air, which can eventually make its way into the rest of your home. Keeping the fan on could pull more cold air upward, increasing the amount of heating you need to remain warm.

If you’re still trying to decide 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 might work for you if:

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

Your home deals with hot and cold spots. All kinds of homes wrestle with difficult 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 consistently refreshing each room’s airflow.