Centralised or Decentralised Air Conditioning?

Updated: Jul 14

May I start by welcoming you on our web page? We are here to give you information about centralised and decentralised Air Conditioning systems. Many design consultants and engineering companies provide such kind of HVAC solutions and it can get pretty confusing for people who don't know what it is or what is the difference between those two systems.

Centralised Air Conditioning Systems

Centralised air conditioning systems have been used for decades, and they are still widely designed by building services consultants and used in commercial buildings today. The centralised system uses a single unit to provide cooling throughout a building. There are several advantages to this type of system, including:

  • Lower installation costs than other types of systems because there are fewer units to install;

  • Lower operating costs because there are fewer units to maintain;

  • More efficient use of energy because there is only one compressor; and

  • Reduced risk of failure because if one unit fails, others do not fail as well.

The main disadvantage is that it uses more space than decentralised systems, which means that it may not be suitable for smaller buildings or homes where space is limited. Also, if there is a problem with the central unit, it will affect all areas within the building – so if you want individual control over each room then this isn’t possible with a centralised system. Also, they require more ductwork than decentralised systems, which may make them too expensive for some homeowners. They also require more maintenance than decentralised units because of their complexity. Although these systems are quite popular for hotels, schools, offices and the other commercial applications, due to the mentioned reasons some building services design consultants may avoid using them.

Decentralised Air Conditioning Systems

Decentralised air conditioning systems are less energy efficient and less convenient, but they're much cheaper to install. In a decentralised system, there's no one big unit that does everything; instead, there are several smaller units throughout your home or building. Each unit has its own evaporator coil and condenser coil connected by copper pipes. There's no need for valves or unions because each unit's parts are all together in one place. The most common type of decentralised air conditioning systems would split systems that come in different types of wall mounted, cassette, ducted, under ceiling, etc.

In a decentralised air conditioning system, there are fewer parts involved than in centralised systems because they are located near where they're needed rather than all being concentrated together in one place. However, they require more maintenance because they're designed to fit into small spaces like attics or crawlspaces where it's harder for maintenance technicians to get at them when they need servicing or repair work done on them. There are some advantages for decentralised systems including:

  • Control over temperature – You can set different temperatures for different rooms or areas of your home

  • More affordable than centralised systems, as decentralised units are cheaper to produce and install.

  • Takes up less space than a centralised system.

  • Can be installed in any room or area of the house without affecting other rooms/areas of the house.

If you or your design consultants are choosing between a centralized or decentralized air conditioning system, it's important to consider the specific benefits of each one. Both of these systems have their pros and cons. Centralised Air conditioning is good for areas with high ambient humidity, as it requires less water. However, this comes at the cost of higher energy consumption due to evaporation. In recent years, a number of engineering companies made progress in improving air-conditioning devices, such as retrofitting to adjust indoor temperature according to users' habits. So centralised air conditioning is becoming more and more popular in modern society. Decentralised Air Conditioning is a viable option where there is low ambient humidity or high water availability in the area. The costs associated to installation are reduced as well.


The choice of which system to use ultimately comes down to the cost effectiveness of each. One has higher installation costs, but lower energy and water consumption. The other has less costly installation, but higher energy and water consumption. Which will be most cost effective? It depends on the environment and the location.

Get in touch to discuss your requirements with our engineering team: info@sustena.com.au







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