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  • Writer's pictureAircon Hero

How does a wall mounted aircon work?

Modern wall-mounted air conditioners are a popular choice for cooling individual rooms or smaller spaces. They are designed to provide efficient and targeted cooling while taking up minimal space. Understanding how these units work can help users make the most of their air conditioning system and optimize its performance. Wall mounted units are the most common type that Aircon Hero technicians work with when it comes to residential clients.


A wall-mounted air conditioner consists of two main components: an indoor unit and an outdoor unit. The indoor unit, also known as the evaporator, is typically mounted on a wall within the room being cooled. It contains a cooling coil, a blower, and control components. The outdoor unit, called the condenser, is installed outside the building and houses the compressor, condenser coil, and a fan.


Wall mounted aircon in Malaysia

The process of cooling begins when the air conditioner is turned on and the thermostat is set to the desired temperature. Here's a step-by-step explanation of how a modern wall-mounted air conditioner works:


  1. Air Circulation: The blower fan inside the indoor unit draws warm air from the room through the air return vent. This warm air passes over the cooling coil, also known as the evaporator coil, which contains a refrigerant. The refrigerant absorbs the heat from the air, causing the air to cool down.

  2. Heat Absorption: The refrigerant, usually in a gaseous state, enters the evaporator coil at low pressure. As warm air passes over the coil, the refrigerant absorbs heat from the air, causing it to evaporate into a gas.

  3. Compression: The gaseous refrigerant is then drawn into the outdoor unit, where it enters the compressor. The compressor increases the pressure of the refrigerant, which also increases its temperature.

  4. Heat Discharge: The high-pressure, high-temperature refrigerant then flows through the condenser coil located in the outdoor unit. The condenser coil is designed to dissipate heat effectively. As outdoor air blows across the condenser coil, the heat from the refrigerant is transferred to the surrounding air, causing the refrigerant to condense back into a liquid state.

  5. Expansion: The high-pressure liquid refrigerant, after releasing its heat, passes through an expansion valve. The expansion valve reduces the pressure and temperature of the refrigerant as it enters the evaporator coil of the indoor unit, starting the cycle again.

  6. Cool Air Distribution: Once the refrigerant has been expanded, it becomes a low-pressure, low-temperature gas and absorbs heat from the air passing over the evaporator coil. The cooled air is then blown back into the room by the blower fan, providing a comfortable and cool environment.

This continuous cycle of refrigerant circulation allows the wall-mounted air conditioner to extract heat from the indoor air and transfer it outside, effectively cooling the room. The process repeats until the desired temperature is reached and maintained.


Modern wall-mounted air conditioners often come with additional features and settings to enhance comfort and energy efficiency. These can include programmable timers, sleep mode, adjustable fan speeds, and energy-saving modes. It is advisable to refer to the manufacturer's instructions to fully understand and utilize the specific features of your air conditioner.


Wall mounted aircon how they work and service

To ensure optimal performance and energy efficiency, regular maintenance is crucial. This can involve cleaning or replacing air filters, checking refrigerant levels, and cleaning the outdoor unit to prevent any obstructions that may hinder airflow.


In conclusion, modern wall-mounted air conditioners work by circulating refrigerant between the indoor and outdoor units to extract heat from the room and discharge it outside. Understanding the basic functioning of these units helps users make informed decisions and take necessary steps to maintain and maximize their cooling efficiency. And of course, regular servicing of the aircon will ensure longevity and cold air!

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