Air Conditioner Mode Explained: Auto, Dry, ECO & More


Getting new air conditioners is exciting. There are many modes available in an air conditioner but what is the function of each mode and which mode should you use?

Most air conditioners have cool mode, dry mode and fan mode. Some air conditioners come with extra modes such as sleep mode, turbo mode and ECO mode. Heat pumps are equipped with auto mode and heat mode to provide heating.

While the common modes are easy to understand how they work but some of the special modes may be more than meets the eye.

Auto Mode

In auto mode, a cooling only air conditioner usually adjusts the fan speed automatically based on the desired temperature. Some air conditioners adjust the temperature setting to 25°C by default when operating in auto mode.

For a heat pump with both cooling and heating functions, not only the fan speed and temperature will be adjusted automatically, but the heat pump will also switch between cool mode and heat mode accordingly to meet the desired temperature. Such an operation is sometimes called auto changeover mode.

For most air conditioners, you can’t adjust the fan speed manually when operating in auto mode as the air conditioner automatically adjusts the fan speed for you.

Cool Mode

An air conditioner operates in cool mode by default. The air conditioner will cool the room based on the set temperature. The fan speed usually needs to be adjusted manually. However, usually, you can switch to auto fan if you want the fan speed to be adjusted automatically.

In cool mode, not just the fan speed but the temperature, air swing, turbo, sleep, timer and many other modes generally can be adjusted as desired.

Dry Mode

Many people misunderstand that an air conditioner does not provide cooling when operating in dry mode which is false. In dry mode, an air conditioner works exactly as in cool mode. However, the air conditioner’s primary objective is to dehumidify the air instead of cooling the room.

In order to dehumidify or remove moisture, the air must contact a cold surface to incur condensation. Thus, the compressor of air conditioner must work to provide cold refrigerant to the cooling coil. Therefore, an air conditioner not only dehumidifies but also cooling the room when operates in dry mode.

Usually, the air conditioner will run at a fixed fan speed when operating in dry mode and you can’t adjust it. Some air conditioners allow you to set the temperature as desired. Other air conditioners adjust the best fan speed and temperature automatically for dehumidification.

Fan Mode

In fan mode, an air conditioner only operates the indoor fan blower to circulate air. The outdoor fan and compressor will not operate in fan mode. You can adjust the fan speed and air swing as desired. The air conditioner only uses a fraction of the energy when operating in fan mode in exchange for zero cooling.

When using an air conditioner in fan mode, you may notice a different smell coming out from the air conditioner. The smell is usually due to the leftover drain water inside the air conditioner. It is completely normal as long as the smell doesn’t stink.

Heat Mode

Only a heat pump or an air conditioner with a heating function can operate in heat mode. As the name suggested, a heat pump provides heating instead of cooling when operating in heat mode. Just like in cool mode, the fan speed, temperature, air swing, turbo, sleep, timer and many other modes generally can be adjusted as desired when operating in heat mode.

Sleep Mode

Sleep mode usually can only be activated in conjunction with cool, auto and heat mode. When sleep mode is activated, an air conditioner generally will increase the temperature by 1°C (2℉) after 30 minutes. Then, it increases the temperature by another 1°C (2℉) after the subsequent 30 minutes. The increased temperature is maintained for about 7 hours before it automatically resets back to the original temperature setting.

The purpose of sleep mode is to save energy. The air conditioner gradually increases the temperature so that it won’t affect our sleep. It is assumed that people generally won’t feel the temperature rise during sleep. Thus, the air conditioner takes the opportunity to save energy.

Turbo Mode

Other names such as powerful mode and overcool mode are essentially referring to the same function as the turbo mode. Similar to sleep mode, turbo mode can only be activated in conjunction with cool, auto and heat mode.

In turbo mode, an air conditioner will operate at the maximum fan speed and the lowest temperature. Sometimes, the fan speed is beyond the maximum fan speed setting. Then, the air conditioner reset back to the original setting after 30 minutes on average. The duration of turbo mode may vary based on brands and models.

Some air conditioners may not display the maximum fan speed and the lowest temperature setting on their controller while operating in turbo mode. Similarly, a heat pump also can activate turbo mode to heat a room quickly.

Quiet Mode

In quiet mode, an air conditioner reduces the fan speed to the minimum. Sometimes, the fan speed is beyond the minimum fan speed setting. The purpose of quiet mode is to reduce the noise level to as low as possible. The cooling effect of an air conditioner is lessened when operating in quiet mode. Some air conditioners have the ability to activate quiet mode for the outdoor unit to further reduce the noise.

ECO Mode

Generally, when ECO mode is activated, an air conditioner will perform a few tricks to save energy. Depending on the brands and models, an air conditioner may perform some of the following tricks:

  • Motion sensor – Increase the temperature when no movement is detected to save energy.
  • Sunlight sensor – Increase the temperature when the sunlight intensity in a room is low to save energy.
  • Capacity limit – Limit the compressor capacity to save energy with a drawback of reduced cooling.
  • Fan off – Turn off the indoor fan blower when the set temperature is reached to save energy.
  • Temperature increase – Increase the temperature by 2°C (4℉) immediately to save energy.
  • Targeted cooling – Increase the temperature but blow air directly to occupants to save energy while maintaining sufficient cooling.

Some of the ECO mode names are ECONAVI, ECOsense, iSense, Econ mode, intelligent eye and intelligent mode. ECO mode cannot be counted as part of the efficiency of an air conditioner because something else always exchanged for the lower power consumption when operating in ECO mode.

Follow Me Mode

Follow me mode is only available for air conditioners with a remote controller. As the name suggested, when follow me mode is activated, an air conditioner relies on the remote controller to sense the room temperature and adjust its cooling power accordingly. Follow me mode is more likely to be found in portable air conditioners.

Since the remote controller must feedback the room temperature to the air conditioner when follow me mode is activated, the battery may deplete quicker. Thus, the signal feedback interval maybe 30 seconds up to a few minutes to prolong the battery life.

How to Know What Modes Your Air Conditioner Has?

The best way to know what modes your air conditioner has is by referring to the user manual that comes with the air conditioner. Some air conditioners provide a separate user manual for the remote controller. The user manual will show you the available modes and guide you step by step on how to activate each mode. Alternatively, you can check the symbol displayed on the remote controller.

Which Mode is the Best for Air Conditioner?

There is no such thing as the best mode for air conditioners. If you are concerned about energy usage, you should choose a high efficiency air conditioner instead. As mentioned earlier, an air conditioner exchanges something else in order to save energy when ECO mode is activated. However, if you have no trouble with the exchanges, feel free to use ECO mode most of the time.

If you ever feel too cold, try activating quiet mode to reduce the airflow and thus, reduce the cooling effect. Alternatively, you may try dry mode.

Yu Chang Zhen

Yu was working in the air conditioning industry for the past 7 years, covering from design to installation and maintenance. Yu wish to share all the things he learned with the people around the world.

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