Once the weather begins to cool off, you might be thinking about how you’ll prepare your heating and cooling. After all, HVAC costs can contribute a significant portion of your monthly electric bill. To try and find ways to reduce costs, some owners take a closer look at their thermostat. Maybe there’s a setting they should use to improve efficiency?

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

What Is the Fan Setting on My Thermostat?

For most thermostats, the fan setting signifies that the air handler’s blower fan keeps running. Some furnaces may continue to generate heat at a low level in this setting, but for the most part heating or cooling isn’t being produced. The ‘Auto’ setting, on the other hand, will start the fan through a heating or cooling cycle and switch it off after the cycle is over.

There are benefits and drawbacks to using the fan setting on your thermostat, and the ideal option {will|can|should]] depend on your unique comfort requirements.

Advantages to trying the Fan/On setting:

  • You can keep the temperature in each room more uniform by enabling the fan to keep circulating air.
  • Indoor air quality can increase as steady airflow will keep passing airborne pollutants into the air filter.
  • Fewer start-stop cycles for the HVAC fan helps expand its life span. Since the air handler is typically part of the furnace, this means you can avoid needing furnace repair.

Disadvantages to using the Fan/On setting:

  • A nonstop fan can add to your energy bills by a small margin.
  • Continuous airflow can clog your air filter soon, increasing the frequency you should replace it.

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

During the summer, warm air may persist in unfinished spaces including the attic or an attached garage. If you leave the fan on, your HVAC system may pull this warm air into the rest of your home, forcing the HVAC system to run longer to maintain the desired temperature. In serious heat, this may result in needing AC repair more quickly as wear and tear gets worse.

The opposite can occur over 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 will sometimes 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 try the fan/on setting, keep in mind 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 suffers from allergies. Allergies and similar respiratory conditions can be stressful 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 wrestle with difficult hot and cold spots that quickly return to a temperature different from the rest of the house. The fan setting can help minimize these changes by steadily refreshing each room’s ventilation.