HVAC Blower Modes: Pros & Cons

Advantage Air HVAC • February 14, 2023

Significant changes in temperature within your home are a sign you need to run your HVAC fan. HVAC systems come equipped with a blower fan that circulates air to help eliminate hot and cold air pockets. The blower has two modes: on and auto. Both have pros and cons, and Advantage Air HVAC is sharing them with you.

HVAC Fan Spinning

What Does “On” Mean?

An HVAC fan in “on” mode will run continuously regardless of whether your system is actively heating or cooling your home. What are the upsides to this?

  • Your home will have improved air circulation. Even when your system is heating or cooling your home, it cannot properly circulate air. This means hot air will rise and cooler air will fall, leading to uncomfortable temperatures throughout your home.
  • Keeping the fan turned on will increase its lifespan. Frequent starting and stopping places stress on the fan, and allowing it to remain on reduces this.
  • When you circulate air more often, it doesn’t have a chance to get stuffy.
  • Since you have to take the good with the bad, here are the cons of having your fan on:
  • Fans use energy, so running your HVAC blower 24/7 will cause higher energy bills. The average HVAC fan motor is 500 watts. Running the fan continuously for one month will use 360,000 watts or 360 kilowatt hours (kWh), which will cost approximately $43 per month at the average rate of $0.12 per kWh.
  • When the fan is on, air passes through the filter. This means the air in your home will be healthier, and you will need to replace the filter more often.

What is “Auto” Mode?

When in auto mode, your HVAC fan will only run while the system is heating or cooling your home. Once the thermostat reaches the set temperature, the system and blower fan will turn off. This mode is good for two reasons:

  1. It’s more energy efficient. Anytime the fan is not running, it’s not using any power.
  2. Your home’s air will be less humid. When the fan is off, the moisture on the condensation coils will fall into the drain pan instead of being blown throughout your house.

Reasons to avoid auto mode:

  • You’ll experience uneven temperatures in different areas of your home.
  • Every time the motor turns on or off, it reduces lifespan.

So, Which is Better?

Unfortunately, we can’t give you a concrete answer to this question. Since both modes have benefits and drawbacks, your personal preference should be your guide. Investing in a smart thermostat will allow you to set timers for your fan so it will run a certain amount of time, regardless of whether the HVAC system is running. Fans with variable speed technology are another solution. The option to run the fan at a lower capacity means more effective and efficient use.

Contact Us

The pros at Advantage Air HVAC are here to answer your blower fan questions. We’ve been serving the area since 2007, and our team has over 30 years of combined industry experience. You can count on us for your residential and commercial HVAC needs, eco-friendly and geothermal heating and cooling. Our office is in Lexington, KY, and we are proud to serve Versailles, Winchester, Georgetown, Paris, Wilmore, Nicholasville, and the surrounding areas. Send us a message or call us today at (859) 559-6409.

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