How central air conditioning systems work and why you need them

At home, we’re typically used to seeing window-mounted or split air conditioners, which are suitable for smaller spaces and are usually only used for a few hours at a time. However, in commercial spaces, hotels, and even in some modern apartment buildings, you might see a central air conditioning system. It’s a much more efficient cooling system for large spaces and populated spaces such as office floors or shopping malls, with a single set of equipment, air ducts, and vents simultaneously offering cooling to an entire large space.

It’s also important to note that a central AC system isn’t just one appliance and can be quite complicated to set up because of its construction and operational requirements. There isn’t just one central air conditioner – it’s a complex network of equipment all working together. However, depending on the size of the space you need to cool, and the number of people that could be present in that space, it might make sense to invest in a good central air conditioning system for your location.

Modern homes – especially new apartment buildings – could also benefit from a central AC system. It is a lot easier to set up and maintain during and after building construction, and often looks more aesthetically pleasing in the home itself, apart from requiring little specific setup or maintenance in individual homes. Just like electrical and plumbing systems, a central AC system can also be maintained collectively and centrally for the entire building.

How central ACs work

The functioning of a central AC primarily revolves around the following components.

1. Central unit

The central main unit of a central AC consists of the compressor, condenser, and evaporator. This unit is generally located outdoors.

2. Air ducts

These are the medium through which cooled air is circulated from the central unit across a space. 

3. Vents and registers

Vents and registers are strategically located in every room to distribute cooled air into the space.

4. Refrigerants

Central AC systems use refrigerants to absorb and release warmth from the air, as it moves across a space.

Benefits of a central AC system

Here are a few reasons why you may want to consider investing in a central AC, specially if you happen to work or live in a large space.

1. Consistent cooling

One of the primary advantages of a central AC system is that it can maintain a cool and consistent temperature throughout large spaces. 

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2. Energy efficiency

Central AC systems are known for their energy efficiency. By cooling an entire space from a single point, they eliminate the need for multiple units, lowering energy consumption and electricity bills.

3. Reduced noise levels

Since the components of a central AC which generally tend to be noisy are placed outside, indoor noise levels from central ACs is considerably low, when compared to conventional models.

4. Aesthetic appeal

Central AC systems are mostly concealed, which helps provide for a cleaner looking, less cluttered space. 

5. Easy control

With a central AC, one can change the temperature of the entire space througout, or even individual zones from a single control panel, making them very easy to operate.

6. Reduced maintenance requirements

While central AC systems consist of a fairly complex network of ducts, one cannot overlook the fact that maintaining a single AC unit is easier far easier, both in terms of energy, effort and money, than maintaining multiple units.

7. Longevity

Central AC systems, by design, have a longer lifespan as compared to conventional ACs.

Central air conditioning system: Installation

As mentioned, central AC systems are very complex to setup and install, and ideally should be done at the building construction stage. That said, central air conditioning can also be implemented later, but the cost and complexity of the installation will naturally increase, as will the effort that goes into maintaining such a system.

Installation usually involves setting up of multiple outside cooling units – usually on the roof or terrace of the building – along with a network of pipes to bring the cool air into all desired spaces within the structure. Central air conditioners can also be controlled in rooms by setting the temperature or fan speed, and the system will adjust the flow to adjust to the desired level of cooling.

Central air conditioning system: Maintenance

A central air conditioning system can be quite complicated to maintain, and is thus ideally in place in a collective setting or for a large space which would not be possible to cool with individual split units. However, once in place, the system can be maintained efficiently and regularly through the changing of air filters, cleaning or periodic replacement of condenser coils, coolant replenishment, and professional tune-ups for the entire system.

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Multiple cooling units placed in a single, easily accessible space will also help, and individual cooling units failing will not significantly impact the overall system in the short term. Additionally, the system can be increased or decreased collectively and automatically depending on requirements, with cooling units turning on or off as needed.

Common issues such as individual unit failures or pipe leaks can be identified and tackled efficiently without impacting the entire system. Issues such as uneven cooling, airflow problems, and refrigerant leaks can be handled similarly and at a localised level.

Central air conditioning system: Energy efficiency

When used in a large space such as a big multi-storey home or an apartment building, a central AC can be operationally much more efficient than a window or split AC in terms of energy consumption. Since the cooling units are utilised collectively, this ensures that the overall system uses only as much energy as is needed, while delivering many hours of cooling through the day. A well-maintained central AC system is likely to achieve very good SEER and energy star ratings too.

Similarly, a central AC system could even be switched off for a few hours at a time without significantly losing out of the cooling. You could also install a programmable thermostat to automate cooling and energy consumption levels according to time of day and ambient temperatures.

Central air condition system: Frequently asked questions

How long does a central AC system last?

If well maintained, a central AC system can last upwards of 20 years. However, this depends on the frequency of its use, the outside weather, and other similar factors.

Can I retrofit a central air conditioner into an older home?

Yes, retrofitting a central air conditioning system into an older home is possible, but it will require considerable structural and functional changes. Such a setup might be expensive, but could work out through savings and efficiency in the long run.

What size central AC unit do I need for my home?

This naturally depends on the size of your home, and smaller homes are usually more effectively cooled by regular window or split air conditioners placed in different rooms. Larger and more open and spread out spaces would need approximately 3-4 tons of capacity per 1,000 square feet of area to be cooled, which can be combined and operated collectively using a central air conditioning system.

A central AC system, while typically seen in commercial and large indoor spaces such as malls and offices, could thus be practical to install even in a home environment. However, it’s best to seek expert advice on which type of air conditioning system will be best for your home.