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The Importance Of Having A Correctly Sized Air Conditioning System

Adelaide can suffer through scorching hot summers and freezing cold winters, so it pays to have the perfect heating and cooling system in your home. When it comes to purchasing an air conditioning system, there are many things that need to be taken into consideration. One of the most important ones is the size of the system itself. You may feel as though it is wise to save a few pennies and choose the undersized system, or maybe you have been told that ‘bigger is better’? If any of these circumstances seem the same to you, then it may be wise to read on.

The sizing for air conditioners works on kilowatts (kW) capacity output and is dependent on a number of elements. The best way to determine what capacity is needed is to have a professional size the system for you. They will look at all of your room requirements:
– whether you are wanting to cool your entire home or just a single room;
– the size of the room or home;
– the insulation within your walls;
– the purpose of the room (i.e. is a gym room or a lounge room?);
– the number of windows;
– the climate that you live in;
– the height of your ceilings and much more.

From all of this information, they can determine the exact capacity required to suit your needs. If they are offering you a system without first asking you a few crucial questions, then that system may not be the right one for your home.


Why is it important to get the capacity size right?

It is a general belief that an air conditioning system that is oversized for your space must be better because they can quickly and easily cool your home. This is not true. So why is it important to have a system in your home that is the correct size…

If it is undersized

If a system is undersized for a space, there are many issues that may arise. The first and most obvious one is that it will be unable to cool or heat the space efficiently. As an undersized system does not have the power it needs, the unit will need to consistently work at its maximum to reach and then maintain the desired temperature. The biggest issue with an undersized system is overworking which increases the risk of breakdown and severe wear and tear and can shorten the lifespan of the system. This constant need to run at its maximum also consumes a large amount of energy, meaning you end up paying more on your bills.

If a system is oversized

Having an oversized system installed under the assumption that a larger air conditioner will work more efficiently, is just as detrimental, if not, worse.

The first issue is that oversized systems work TOO efficiently for the space that they are cooling. This leads to a process called short-cycling. When an air conditioner cools the room to the desired temperature, the thermostat signals the unit to shut off. When the temperature in the room rises again, the system turns back on, quickly cooling the room down and the cycle continues. This frequent switching on and off leads to significant wear and tear on the system as well as largely increased energy bills.

Think of it the same as driving a car. You put your foot down quickly on the accelerator to reach your desired speed and then take it off. When the car slows down, you put your foot back on the accelerator quickly and then take it off again. By intermittently accelerating your car instead of gradually reaching your desired speed and maintaining it, you consume more fuel.

Short-cycling can also lead to temperature changes in the room and minimised humidity control. If the system cools the room down too rapidly, it does not have enough time to remove the moisture from the air. Both of these issues lead to a large amount of daily discomfort and wasted money.


The only way to be sure that you have the correct system in your home is to have a professional measure it up for you before installation. The installer must to a complete load calculation to find the correct size, taking into account all of the contributing factors mentioned above, such as room size, home location, personal desires, etc. They will then be able to find the most suitable system for your home that will provide the most comfort, run efficiently and last longer.

If you already have a system installed in your home and are concerned about whether or not it is the right size, or are thinking about having one installed, call us today on (08) 8297 3422 for a FREE quote.

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