When the weather begins to cool off, you might be wondering about how you’ll make the most of your heating and cooling. After all, HVAC costs can make up a significant piece of your monthly electric bill. To figure out new ways to lower their HVAC bill, some homeowners take a closer look at their thermostat. Maybe there’s a setting they can use to boost efficiency?

Most thermostats include both a ‘Fan’ or ‘Fan On’ setting. But if the fan is going during a regular cycle, what will the fan setting offer for the HVAC system? This guide should help. We’ll walk through just what the fan setting is and whether you can use it to cut costs in the summer or winter.

My Thermostat Has a Fan Setting?

For the bulk of thermostats, the fan setting indicates that the HVAC blower fan stays on. Some furnaces can generate heat at a low level in this setting, but for the most part heating or cooling isn’t being generated. The ‘Auto’ setting, in contrast, will turn on the fan during a heating or cooling cycle and turn it off once the cycle is over.

There are pros and cons to switching on the fan setting on your thermostat, and the ideal option {will|can|should]] depend on your personal comfort requirements.

Advantages to using the Fan/On setting:

  • You can keep the temperature in each room more balanced by permitting the fan to keep circulating air.
  • Indoor air quality will be highest as continuous airflow will keep passing airborne pollutants into the air filter.
  • Fewer start-stop cycles for the blower fan helps extend its life span. Since the air handler is usually a component of the furnace, this means you can prevent the need for furnace repair.

Drawbacks to switching to the Fan/On setting:

  • A constant fan will likely increase your energy costs by a small margin.
  • Nonstop airflow can clog your air filter in a shorter amount of time, increasing the frequency you should replace it.

Which Setting for My Thermostat? Fan or Auto in Each Season

During the summer, warm air can persist in unfinished spaces such as the attic or an attached garage. If you use the fan setting, your HVAC system may draw this warm air into the rest of your home, compelling the HVAC system to run longer to maintain the set temperature. In extreme heat, this could lead to needing AC repair more regularly as wear and tear gets worse.

The opposite can happen during the winter. Cooler spaces like a basement will hold onto cooler air, which can eventually make its way into the rest of your home. Leaving the fan running could pump more cold air upward, increasing the amount of heating you need to keep warm.

If you’re still trying to figure out if you should use the fan/on setting, remember that every home and family’s comfort needs will vary. Leaving the HVAC system’s fan on could be best for you if:

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

Your home experiences hot and cold spots. Lots of homes deal with difficult hot and cold spots that quickly shift to a temperature different from the rest of the house. The fan setting should help limit these changes by steadily refreshing each room’s supply of air.