This, of course, wouldn’t work too well in sunny Singapore, where humidity hovers around the 90 per cent mark! If you’re torn between using air-conditioning and resolving to guzzle less energy at home, get the most efficient cooling system available and keep it in tip-top condition.


Modern-day air-conditioning systems mounted on your wall/ceiling/window cool your space by running the air in the room past pipes filled with refrigerant in the fan coil unit (which removes the heat), and then dispensing the cooled air back into the same room. Humidity is simultaneously removed from the air — the fan coil causes humidity to condense on the surface — making the enclosed environment even cooler. In the compressor, the heated refrigerant is run past the condenser fans to return it (the heated refrigerant) to a cooler state before heading back to your fan coil unit; rinse and repeat.

Examine the many different models available from any air-conditioning system brand, and you’re likely to encounter terms such as ceiling ducted, wall-mounted and window unit. There are four basic types of air-conditioning systems you should be aware of (see sidebar overleaf), however, and only one word you should really look out for when purchasing a new air-conditioning system — «inverter».


The most energy-efficient air-conditioner available today is the inverter system. Previously, air-conditioning units worked either at maximum capacity, or were switched off entirely. This means consistently cool air from your air-con, while consuming the least amount of energy possible.

It is impractical to dictate exactly how much cooling is enough for everyone — this is a personal preference. Let’s start with the basics: space. To determine the capacity of air-conditioning you require, simply find the approximate volume of the room you wish to cool, and multiply that number (in cubic feet) by 25 — that is about the capacity you require for your air-conditioning unit.

The capacity is important because if your unit is too small, it has to run at a higher output for a longer period of time. If it’s too large, the air reaches the set temperature quickly enough but the humidity isn’t removed, which affects how «cool» we feel in the enclosed space.


An air-conditioning unit is a complex machine with many different parts. During the installation process, the wiring and piping will usually be done ahead of the painting, carpentry, and other work. Next, a bracket will be installed to hold the compressor, while the fan coil unit is mounted in the requisite rooms. A water pipe must run from each unit to a drainage pipe, as there will be condensation on the evaporation coil. Most of the time, the pipes and wiring will be enclosed in a casing to provide protection; they may also be concealed in a false ceiling. Take extra care to ensure that your refrigerant pipe is well-insulated to ensure maximum cooling efficiency. Also, check that your compressor is placed in a well-ventilated space so it will work optimally.

Most modern air-conditioners come with filters, which remove particles in the air stream flowing to and from your fan coil unit. Maintaining your air-conditioning system primarily revolves around cleaning and replacing these filters. If the filters get too loaded with particles, air flow will drop, and the system will not perform as well — at which point we reach for the remote and turn down the temperature setting while simultaneously turning up the fan speed. Why have the filters at all, you ask? Without them, airborne particles would build up on the evaporator coil and eventually cause permanent damage. Changing the air filters costs much less than replacing an evaporator coil. During maintenance, the technician will also flush the system and may replace your refrigerant.

If you’re using an air-conditioning system that is over five years old, and isn’t an inverter system, you should consider switching to a new model, even if you’ve maintained it religiously. Changing from a non-inverter split system to an inverter version means more energy savings and up to 30 per cent off your cooling bill.

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