is on or auto best for your thermostat fan setting?
January 11, 2024

The Benefits of Leaving Your HVAC Fan (aka Blower Motor) Set to “On” Instead of “Auto”

The HVAC (Heating, Ventilation, and Air Conditioning) system plays a crucial role in maintaining indoor comfort and air quality. One often overlooked aspect of the HVAC system is the fan setting—specifically, whether to leave it on “Auto” or “On.”

The Difference between “Auto” and “On”:

Let’s understand the basic distinction between the two settings:

Auto Mode:  In this mode, the fan operates only when the heating or cooling system is actively running.  The fan shuts off once the desired temperature is reached, and it remains idle until the next heating or cooling cycle begins.

On Mode: The fan operates continuously, regardless of whether the heating or cooling system is actively running.  This setting ensures a constant circulation of air throughout the home.

Advantages of Leaving the Fan on “On”:

Improved Air Circulation:  One of the main benefits of leaving the fan set to “On” is that it provides continuous air circulation. This helps in distributing air more evenly, preventing hot or cold spots in different areas of the house.

Air Filtration: Running the fan continuously allows the HVAC system’s air filter to capture more airborne particles. This can contribute to improved indoor air quality by reducing dust, allergens, and pollutants.

Balanced Humidity Levels: Continuous air circulation helps in maintaining more consistent humidity levels throughout the home. This can be particularly beneficial in preventing the growth of mold and mildew.

Quieter Operation: In “On” mode, the fan runs at a lower speed compared to when it cycles on and off during the heating or cooling process. This can result in a quieter operation, making it less noticeable and intrusive.

If improved air circulation, filtration, and balanced humidity are your priorities, leaving the fan on “On” may be beneficial. Regularly servicing your HVAC system and consulting with a professional can help ensure optimal performance regardless of the fan setting you choose.