As the weather is cooling off, you are probably concerned about how you’ll make the most of your heating and cooling. After all, HVAC costs frequently contribute a significant piece of your monthly electric bill. To figure out new ways to reduce costs, some owners look closer at their thermostat. Could there be 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 will the fan setting offer for the HVAC system? This guide will help. We’ll review precisely what the fan setting is and when you can use it to reduce costs during the summer or winter.

Should I Use My Thermostat's Fan Setting?

For the bulk of thermostats, the fan setting means that the HVAC blower fan keeps running. A few furnaces will operate at a low level in this setting, but in general heating or cooling isn’t being produced. The ‘Auto’ setting, in contrast, will run the fan through a heating or cooling cycle and switch it off when the cycle is complete.

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

Advantages to using the Fan/On setting:

  • You can keep the temperature in each room more balanced by enabling the fan to keep generating airflow.
  • Indoor air quality should improve because steady airflow will keep forcing airborne particles through the air filter.
  • A smaller number of start-stop cycles for the system's fan helps expand its life span. Since the air handler is usually part of the furnace, this means you can avoid needing furnace repair.

Downsides to utilizing the Fan/On setting:

  • A constant fan could increase your energy costs somewhat.
  • Nonstop airflow can clog your air filter in a shorter amount of time, increasing the frequency you’ll need to replace it.

{Choosing Between|Should My Thermostat Be on|Which Setting for My Thermostat? Fan or Auto in Each Season

In the summer, warm air will sometimes stick around in unfinished spaces including 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, compelling the HVAC system to work harder to maintain the desired temperature. In serious heat, this could result in needing AC repair more regularly as wear and tear gets worse.

The reverse can occur during 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. Leaving the fan setting on will sometimes pump more cold air upward, increasing the amount of heating you need to keep warm.

If you’re still trying to determine if you should switch to the fan/on setting, remember that every home and family’s comfort needs are different. Leaving the HVAC system’s fan on could be best for you if:

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

Your home has 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 lessen these changes by consistently refreshing each room’s supply of air.