Once the weather starts to cool off, you are probably wondering about how you’ll prepare your heating and cooling. After all, HVAC bills routinely make up a significant portion of your monthly electric bill. To try and find ways to reduce costs, some owners look closer at their thermostat. Maybe there’s 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 on during a typical cycle, what can the fan setting offer for your HVAC system? This guide will help. We’ll review precisely what the fan setting is and how you can use it to cut costs over 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. A few furnaces can run at a low level in this setting, but in most cases heating or cooling isn’t being made. The ‘Auto’ setting, on the other hand, will start the fan through a heating or cooling cycle and turn it off once the cycle is over.

There are benefits and drawbacks to using 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 every room more balanced by allowing the fan to keep generating airflow.
  • Indoor air quality will be highest as steady airflow will keep moving airborne contaminants into the air filter.
  • A smaller number of start-stop cycles for the system's fan helps extend its life span. Since the air handler is often part of the furnace, this means you can prevent the need for furnace repair.

Downsides to using the Fan/On setting:

  • A continuous fan could increase your energy expenses slightly.
  • Continuous airflow could 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

During the summer, warm air may stick around in unfinished spaces like the attic or an attached garage. If you leave the fan on, your HVAC system can pull this warm air into the rest of your home, compelling the HVAC system to run longer to preserve the set temperature. In serious heat, this could lead to needing AC repair more regularly as wear and tear increases.

The opposite can happen in 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 could pull more cold air upward, increasing the amount of heating you need to stay warm.

If you’re still trying to decide if you should switch to the fan/on setting, don’t forget that every home and family’s comfort needs will vary. Leaving the HVAC system’s fan on may be ideal for you if:

Someone in your household has allergies. Allergies and other respiratory conditions can be stressful on the family. Leaving the fan on is more likely to enhance 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 shift to a temperature different from the rest of the house. The fan setting can help minimize these changes by constantly refreshing each room’s airflow.