When the weather is cooling off, you may be thinking about how you’ll make the most of your heating and cooling. After all, HVAC bills routinely add up to a big portion of your monthly electric bill. To try and find ways to reduce costs, some people look closer at their thermostat. Could there be a setting they can use to improve efficiency?

The majority of thermostats have a ‘Fan’ or ‘Fan On’ setting. But if the fan is going during a normal cycle, what will the fan setting offer for your HVAC system? This guide should help. We’ll walk through what exactly the fan setting is and how you can use it to save money over the summer or winter.

What Is the Fan Setting on My Thermostat?

For the majority of thermostats, the fan setting means that the HVAC blower fan keeps running. Some furnaces may continue to operate at a low level with this setting, but for the most part heating or cooling isn’t being generated. The ‘Auto’ setting, conversely, will start the fan over a heating or cooling cycle and shut 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 trying the Fan/On setting:

• You can keep the temperature throughout your home more consistent by enabling the fan to keep generating airflow.
• Indoor air quality should improve since steady airflow will keep passing airborne contaminants into the air filter.
• A smaller amount of start-stop cycles for the blower fan helps lengthen its life span. Since the air handler is usually a component of the furnace, this means you might prevent the need for furnace repair.

Drawbacks to switching to the Fan/On setting:

• A constant fan could raise your energy bills slightly.
• Nonstop airflow may clog your air filter in a shorter amount of time, increasing the frequency you will want to replace it.

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

During the summer, warm air can stick around in unfinished spaces like 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, pushing the HVAC system to work harder to preserve the set temperature. In extreme heat, this could result in needing AC repair more regularly as wear and tear grows.

The opposite can occur in the winter. Cooler spaces like a basement will hold onto cooler air, which may eventually drift into the rest of your home. Keeping the fan on will sometimes draw more cold air upward, increasing the amount of heating you need to keep warm.

If you’re still trying to determine if you should try the fan/on setting, don’t forget that every home and family’s comfort needs will vary. Leaving the HVAC system’s fan on could work 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 should help to improve 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 evolve to a temperature different from the rest of the house. The fan setting can help lessen these changes by consistently refreshing each room’s airflow.