When the weather begins to cool off, you are probably concerned about how you’ll take full advantage of your heating and cooling. After all, HVAC bills frequently add up to a large chunk of your monthly electric bill. To figure out new ways to lower their HVAC bill, some owners take a closer look at their thermostat. Is there a setting they could 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 will the fan setting provide for your 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 the majority of thermostats, the fan setting means that the air handler’s blower fan remains on. Some 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, conversely, will turn on the fan over a heating or cooling cycle and switch it off once the cycle is finished.

There are advantages and disadvantages to switching on the fan setting on your thermostat, and what's ideal {will|can|should]] depend on your unique comfort requirements.

Advantages to trying the Fan/On setting:

  • You can keep the temperature in every room more consistent by allowing the fan to keep generating airflow.
  • Indoor air quality will be highest because constant airflow will keep forcing airborne particles through the air filter.
  • A smaller amount of start-stop cycles for the blower fan helps expand its life span. As the air handler is typically part of the furnace, this means you could avoid needing furnace repair.

Downsides to switching to the Fan/On setting:

  • A nonstop fan could increase your energy expenses slightly.
  • Constant airflow may 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 stick around in unfinished spaces including the attic or an attached garage. If you keep the fan running, your HVAC system may gradually move this warm air into the rest of your home, compelling the HVAC system to work more to keep up with the desired temperature. In severe heat, this could lead to needing AC repair more regularly as wear and tear gets worse.

The opposite can occur over the winter. Cooler spaces such as a basement will hold onto cooler air, which can eventually drift into the rest of your home. Leaving the fan setting on may draw more cold air upward, increasing the amount of heating you need to remain warm.

If you’re still trying to decide if you should use the fan/on setting, keep in mind that every home and family’s comfort needs will vary. Leaving the HVAC system’s fan on could be ideal for you if:

Someone in your household suffers from allergies. Allergies and other respiratory conditions can be tough on the family. Leaving the fan on is more likely to enhance indoor air quality, helping your family breathe easier.

Your home has hot and cold spots. All kinds of homes deal with persistent hot and cold spots that quickly shift to a temperature different from the rest of the house. The fan setting might help minimize these changes by consistently refreshing each room’s airflow.