Air Conditioner Auto Mode Explained

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Updated May 16, 2023

The best air conditioners come with thermostat settings that owners can use to increase effectiveness and bring down the cost of utility. One of the fairly ubiquitous settings across all modern central air conditioner units is the “AUTO” mode. Your AC’s Auto mode will help conserve energy by only using the compressor when the temperature in the room reaches a certain preset temperature. Let’s look at what AUTO mode means on an air conditioner and how you can use it to get the most out of your AC unit.


  • AUTO mode is used to cut down on energy costs, optimize humidity levels, and keep the indoor temperature at an ideal level.
  • You can set the AUTO mode with the remote control; it cycles on the COOL mode and fan whenever the temperature strays from the desired level.
  • While AUTO provides a better temperature quality, ON mode is better for air filtration and can provide a better indoor air quality.

If you are on a mission to understand all you can about air conditioner controls, we have another article that explains a general question among clueless AC owners worldwide: what do aircon symbols mean?

What is AUTO Mode?

The use of AUTO mode has risen in esteem among owners trying to save on money for its ease of use and efficiency by sensing the air temperature in a room. Then, AUTO mode switches on the COOL mode (compressor) and the air conditioner fan when the temperature goes above or below your desired number.

Insider Tip

To further improve your AUTO setting efficiency, you can look into upgrading to a variable speed system. This option controls the fan speed at all times to optimize energy efficiency.

The benefits of using the AUTO mode are twofold. It’s sort of like energy-saver mode on an air conditioner, but not fully like it. On the one hand, you have better, more comfortable indoor air quality. On the other, you are more energy-efficient, similar to how leaving the air conditioner on when you’re not home saves you money. The alternative to AUTO is the “On” mode. Here, both the fan and compressor (the part that controls the COOL mode) are on constant blast.

For a deeper explanation of some of the terminology in the HVAC world, we have another article that covers what BTU means on an air conditioner.


If you switch your AC to ON mode, you will dirty the air filter quicker than AUTO.

Benefits of Using AUTO

There are a few key benefits to using AUTO mode on your air conditioner. These include:

  • More Accurate ambient temperature
  • More energy efficient
  • Better humidity levels

When Not to Use AUTO

The one area when ON has a leg up on AUTO is with air filtration. Because the ON setting keeps the fan mode in constant use, this will provide better air filtration. For example, it might be good to use the ON mode instead of AUTO if you’ve done in-home construction and have more small particles in the air than usual.

STAT: HVAC experts claim that the ON setting, on average, causes an AC to run for 200 hours more each month than the AUTO mode. (source)


What to do if the AC remote control is lost or broken?

Call the air conditioner manufacturer and see if you can get a replacement. You also can purchase a smart system that allows you to control your thermostat from your phone.

What does the ECO mode do?

Like AUTO mode, ECO mode regulates the compressor and fan to save energy. But ‌this setting might set the temperature higher than usual to save energy costs.

Should my thermostat be on ON or AUTO?

Experts will say that AUTO is the way to go, but the ON setting has its benefits, such as better air filtration.

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