How Does the Outdoor Unit of a Split AC Work? 2023 Guide

Have you ever wondered how a split AC system keeps your home cool during the hot summer months? The outdoor unit of a split AC system is an essential component that plays a vital role in cooling your home. However, understanding how it works can be confusing for some people.

In this blog post, we’ll explain how the outdoor unit of a split AC system works, the components that make it up, and how it cools your home. By the end of this post, you’ll have a better understanding of your split AC system and how it keeps your home cool and comfortable.

What is a Split AC System?

A split AC system is a popular type of air conditioning system that is commonly used in homes and commercial buildings. The system consists of two primary components, an outdoor unit and an indoor unit.

The outdoor unit contains the compressor, condenser, and expansion valve, while the indoor unit contains the evaporator and air handler. The two units are connected by a refrigerant line that circulates refrigerant between the two units.

Components of the Split AC Outdoor Unit

The outdoor unit of a split AC system consists of several components, including a compressor, a condenser, and an expansion valve.

The compressor is responsible for compressing the refrigerant, which increases its temperature and pressure.

The condenser is responsible for removing heat from the refrigerant and transferring it to the outdoor air.

The expansion valve regulates the flow of refrigerant and reduces its pressure, which causes it to cool down.

How Does the Split AC Outdoor Unit Work?

The outdoor unit of a split AC system works by using a refrigerant to absorb heat from your home’s indoor air and then releasing it to the outdoor air.

The process starts with the compressor compressing the refrigerant, which raises its temperature and pressure. The hot, high-pressure refrigerant then flows to the condenser, where it releases the heat it has absorbed from your home’s indoor air to the outdoor air.

As the refrigerant releases its heat, it begins to cool down and condense back into a liquid. The cooled, high-pressure liquid refrigerant then flows through the refrigerant line to the expansion valve, where its pressure is reduced. This causes the refrigerant to rapidly expand and evaporate, which absorbs heat from your home’s indoor air and cools it down.

The cooled indoor air is then circulated back into your home through the indoor unit. The process repeats itself as the refrigerant continues to absorb heat from your home’s indoor air and release it to the outdoor air.

Importance of Proper Maintenance of Outdoor Unit

Proper maintenance of the outdoor unit is critical to ensuring that your split AC system operates efficiently and effectively.

Regular maintenance includes cleaning the condenser coils, checking refrigerant levels, and ensuring that all components are working correctly. Neglecting maintenance can lead to decreased efficiency, higher energy bills, and even premature system failure.

What Happens if Split AC Outdoor Unit is not Working?

If the outdoor unit of a split AC system is not working, it can lead to a range of issues with the overall operation of the system. These issues can include:

  1. No Cool Air: The outdoor unit is responsible for releasing heat absorbed by the refrigerant to the outdoor air. If it is not working, the refrigerant cannot release the heat and will not be able to cool your indoor air.
  2. Reduced Efficiency: A malfunctioning outdoor unit can cause the entire system to operate less efficiently, leading to higher energy bills and increased wear and tear on the system.
  3. System Damage: If the outdoor unit is not working, it can lead to other components in the system, such as the compressor, working harder than they should. This can lead to premature system failure and costly repairs.
  4. Increased Humidity: A malfunctioning outdoor unit can also lead to increased humidity levels in your home, making it feel uncomfortable and clammy.

Why is My Split AC Outdoor Unit Not Working and How to Fix It?

A split AC system’s outdoor unit not working can be caused by a variety of issues, ranging from simple to complex. Some of the common reasons why your split AC outdoor unit may not be working are:

  1. Power Issues: Check if there is a electrical problem like power outage or if the circuit breaker has tripped. If that’s the case, reset the breaker and try turning on the AC again.
  2. Faulty Wiring: Check if the wiring connections to the outdoor unit are loose or corroded. Faulty wiring can prevent the outdoor unit from receiving power, leading to a malfunction.
  3. Dirty Coils: The outdoor unit’s condenser coils can become dirty over time, which can restrict airflow and cause the system to overheat, leading to a shutdown. Clean the coils regularly to prevent this issue.
  4. Refrigerant Leak: A refrigerant leak can cause the outdoor unit to stop working. If you notice a hissing sound or warm air coming from the indoor unit, it could be a sign of a refrigerant leak. Call a licensed HVAC professional to fix the issue.
  5. Faulty Capacitor: The outdoor unit’s capacitor is responsible for providing the necessary power to the compressor and fan motors. A faulty capacitor can prevent the unit from starting up. A professional technician can check and replace the faulty capacitor.
  6. Faulty Compressor: The compressor is the heart of the outdoor unit, and if it fails, the unit will not work. If you hear a clicking or buzzing sound from the outdoor unit, it could be a sign of a faulty compressor. Call a licensed HVAC professional to replace the compressor.

To fix a split AC outdoor unit that is not working, it is recommended to call a licensed HVAC professional. They can diagnose and fix the issue safely and effectively, ensuring that your AC system is back up and running in no time.

Energy Efficiency and Savings

One of the benefits of a split AC system is its energy efficiency. By using a refrigerant to transfer heat instead of using electricity to create cold air, split AC systems can be more energy-efficient than other types of air conditioning systems. This can lead to lower energy bills and greater savings over time.

In addition, newer split AC systems often come with features that further enhance energy efficiency, such as programmable thermostats and variable-speed compressors. These features allow you to control the temperature and cooling settings of your system more precisely, reducing energy waste and increasing savings.

Expert Opinion: As an HVAC expert, I recommend that homeowners invest in regular maintenance of their split AC system to ensure it operates efficiently and effectively. Neglecting maintenance can lead to decreased efficiency, higher energy bills, and even premature system failure.

By taking proper care of your split AC system, you can enjoy cool, comfortable indoor air while also saving money on energy bills. Split AC systems are highly recommended for homes as compared to other HVAC systems like VRF etc.


What is the difference between a split AC system and a window AC system?

A split AC system consists of two separate units, an indoor unit and an outdoor unit, connected by a refrigerant line. A window AC system, on the other hand, is a single unit that is installed in a window or wall opening.

How often should I have my split AC system maintained?

It is recommended that split AC systems be maintained at least once per year, ideally before the start of the cooling season.

Can I install a split AC system myself?

Installation of a split AC system should be performed by a licensed HVAC professional to ensure proper installation and safe operation.

Can a split AC system be used for heating as well?

Some split AC systems are capable of providing both cooling and heating, making them a versatile and efficient option for year-round comfort.

How long do split AC systems typically last?

With proper maintenance and care, split AC systems can last up to 15-20 years, making them a durable and reliable investment for homeowners.

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