10 Things To Consider Before Buying An Air Conditioner​

Air Conditioning
Isaac Jamieson
A person holding a remote control in front of an air conditioner.

What To Consider Before Buying An Air Conditioner

Having an air conditioning has become one of the essential elements for general well-being in people’s homes and businesses.

For many, it is an absolute necessity, and the truth is that we cannot blame them for it. Instead, air conditioning is an essential solution to creating a comfortable environment.

Good air conditioning guarantees better rest, relaxation and mental and physical health. And at work, it can help increase productivity and reduce stress. Nobody likes to work uncomfortably, right? Isn’t it better to work without continually thinking, “OMGsh! How hot is it” or “I’m freezing”?

BUT…there are several things to keep in mind because nobody wants to get stuck with the wrong AC.

I have seen cases where an air conditioner was installed in the wrong spot, and the entire system had to be replaced. That’s an expensive problem that you want to avoid at all costs.

So, to make sure that doesn’t happen to you, read this article, “The Top 10 Things To Consider Before Buying An Air Conditioner”, to the end. This will give you guidelines on what to look for when buying and installing an Air Conditioner.

1. What Type of Air Conditioner Should I Get?

There are several types of air conditioning and many different brands on the market. When looking for an AC for your home or business, the options are reduced to a few.

So, before we go into more depth, I’ll show you some of the most popular types with some pros and cons.

Split System Air Conditioners

A white air conditioner on a white wall.

Split Air Conditioner Systems comprises two units: an indoor unit, the source of heat or cooling and an outdoor unit, connected via pipes.

Multi-Head Air Conditioner Systems are similar to split systems but with one outdoor unit connected to two or more indoor units.


  • Reasonable room temperature control suitable for most homes
  • Simple installation
  • Affordable
  • Efficient


  • The external unit can be noisy
  • They are fixed, so you have to think carefully about where it goes

Ducted System Air Conditioners

A white wall with two air conditioners on it.

Ducted Air Conditioning consists of an outdoor and an indoor unit that is recessed above a false ceiling, so it is protected and does not compromise the aesthetics of the space. You won’t be able to see it with the naked eye.


  • Reasonable room temperature control suitable for most homes
  • Simple installation
  • Affordable
  • Efficient


  • The external unit can be noisy
  • They are fixed, so you have to think carefully about where it goes

Window Wall Air Conditioners

A room with a white brick wall and a white air conditioner.

This type requires only one piece of equipment in which the outdoor and indoor units are integrated. This is placed in a hole in the wall or windows so half the equipment is inside the home and the other half outside.


  • Lower price
  • Easy installation
  • They don’t take too much space


  • Noisy operation
  • They only cool one area
  • Less efficient

Portable Air Conditioners

A white air purifier sitting in a room.

Portable air conditioning systems work similarly to fixed ones, with an integrated compression system under their casing; however, they do not require installation.


  • Lower price
  • Don’t need installation
  • You can move it around


  • Noisy, bulky and heavy
  • Less efficient

2. What Size Air Conditioner Do I Need?

One of the most important initial steps for installing Air Conditioning is to make sure you select the correct size.

When we talk about air conditioner sizing, we are not referring to the dimensions of the appliance itself but the cooling capacity in kW.

Many factors can impact the size that you’ll need. Some of them are:

  • The size of the room, and unit position
  • The insulation of the walls and ceiling
  • The composition of the walls
  • The windows and openings

To achieve the best efficiency and performance, you must ensure that you install the size of the room you want to air condition. 

Having an undersized Air Conditioner installed in a large room is about as good as an ashtray on a motorbike. A large room cannot be cooled by a unit only designed for a small space, while a unit that is oversized gets a room too cold, and would be wasting electricity.

Calculate the size that you need

Generally, in Australia, you will need 0.12 to 0.15 kW of power per m². Now, to calculate the square meters you need to multiply the length and width of the floor of the room. The result will be the square meters of that area.
e.g. 5m length x 4m width = 20m²

Air Conditioner Sizing guide

I have put together a rough guide to the different air conditioner sizes that you’ll need to cool a particular room size.

Room SizeRoom TypeSystem Size
10-25sqmBedroom | Study | Small lounge | Media Room | Office2.5 kW
25-35sqmLarge Bedrooms | Bedrooms with ensuites | Mid-size lounges | Mid-sized kitchens |  Small rooms with high ceilings 3.5 kW
45-60sqmLarge bedroom | Bedroom with ensuites |  Mid-size lounges | Large kitchens | Mid-sized rooms with high ceilings | Offices5-6 kW
60-80sqmLarge lounges | Large open plan areas |  Small shops | Offices7-8 kW

3. What Is The Best Place For Installing Air Conditioning?

The room and the position where you place the indoor and outdoor unit play an important role in the efficiency and performance of your air conditioning.

Where do I install the indoor AC unit?

Not all rooms have the same air conditioning needs. I always start with the drain. You can think you have the best spot for the unit, but if the drain doesn’t flow, it is a huge problem. Once that is taken care of, then choose the position which will provide the ideal amount of airflow. The function of the unit has to be taken into account before its appearance.

Where do I install the outdoor AC unit?

As for the outdoor unit, it As for the outdoor unit, it needs to be placed in a well-ventilated position.

In cool mode, the outdoor unit transfers the heat once inside to the outdoor unit. If a fence or obstacle is in the way, the unit can overheat, causing it to run inefficiently.

The outdoor unit should be installed as close as practical to the indoor unit position to maximise the system efficiency and minimise losses. Most good brands of air conditioners can have the outdoor unit installed up to 20m from the indoor unit without having to add additional refrigerant. However, it’s always best to keep the distance under 5m where possible.

4. What is Energy Efficiency and why is important?

The energy efficiency of air conditioning and heating is generated by each kW of energy consumed. The higher the power generated for each kW spent, the more efficient the unit is.

Every electrical appliance has a label with a different star rating. This energy label allows consumers to quickly and easily know the energy efficiency of their appliances.

In your case, you’ll want to know the energy efficiency of air conditioning to find out which one will consume less power to run. 

A person holding an ipad with an energy efficiency chart on it.

Why is important to have an Energy Efficient Air Conditioner?

  • Save on energy consumption: If your air conditioning is efficient, you can reduce your electricity consumption by 30%.
  • Better operation: The efficiency of the air conditioning is related to the good operation of the equipment. I recommend checking its operation periodically.
  • Environment: If a unit is more efficient, its energy consumption will be much lower and, therefore, it will have a less negative impact on the environment.
  • Less maintenance: We will avoid constant maintenance for malfunction and extend the equipment’s lifespan. An efficient air conditioner would have at least three more years added to its lifespan.

Which type of Air Conditioner units are the most efficient?

Generally, the most energy-efficient type of air conditioner you can buy is a split system. You will notice that the smaller the size of the unit, the more energy efficient they are.

That’s because energy efficiency is based on power consumption, not on how effective the system works.

If you size a unit correctly and choose one of the major brands, I wouldn’t fuss too much over the energy rating. Anything that heats or cools is going to use a lot of power.

5. How Much Does It Cost To Run An Air Conditioner?

Although air conditioning systems have different consumption depending on the brand, the size system and how old it is, it is essential to understand that the kW (kilowatts) size of the unit is how we measure the cooling capacity, but this is not the energy consumption of the unit. Just to confuse you the power consumption is also measured in kW but is only a fraction of the unit cooling capacity rating.

For example, a Panasonic 2.5kw air conditioner (model CS/CU-Z25VKR) has a power consumption of 0.5kw per hour.

As for the daily hours we use, let’s assume that your AC is running around 6 hours per day (3kW) of power.

If we multiply by the average of a week, it would be 7 days x 3 kW = 21 kW of weekly power expenditure.

Then, to calculate the weekly cost, we will simply multiply that figure by the cost of kW (e.g. 25 cents/kWh in Queensland), and we will obtain the total monthly cost as a result.

21 kW x $0.25 = $5.25/week. (This cost is approximate. Calculated per unit)

Cooling vs. heating Which one consumes more energy?

Air conditioners consume more power when they have to work harder, and the by-product of any electric machine is heat!

This is why your air conditioner will always have a higher heating capacity than its cooling capacity. 

As a heater, an air conditioner is quite effective and can reach temperature quite quickly. Typically, we tend to run our air conditioners for extended periods in cooling mode, resulting in higher power consumption when trying to cool a room.

Quick tips for reducing running costs

  • Choose the right AC size
  • Check the Energy Rating and choose an AC with a good energy rating
  • Ensure regular maintenance of your unit
  • Turn on the aircon only when you’re at home

6. How Noisy Should an Air Conditioner Be?

Another important thing that people often overlook when buying an AC is the noise level. You know how annoying it is to have constant background noise when you’re trying to focus on your tasks, right?

Then make sure you check the noise levels before you buy any air conditioner.

To get an idea of what the noise levels look like, check out this table.

0dBThreshold of human hearing
20dBWhisper, light snoring
40dBModerate snoring
60dBBusy street, alarm clock
80dBLoud radio
100dBSubway train
120dBAmbulance Siren
140dBPlane taking off

Each unit has a different noise level of operation and you should be able to find that in its product specifications. Ideally, the noise levels should be under 50dB.

7. What is Inverter technology and why is important?

The solar inverter is an electronic component that alters the compressor’s speed. The inverter regulates the compressor’s pace, so it always works at a constant speed and, therefore, more efficiently. The application of inverter technology in air conditioning equipment affects energy savings.

On the contrary, in non-inverter units, the compressor always works at maximum speed, following an all-or-nothing principle: it operates at maximum performance until it reaches the desired temperature and then stops. Then, when the temperature moves away from the desired one again, it starts working at full power.

By working the compressor continuously with inverter technology, you can notice around a 50% reduction in energy consumption compared to conventional devices.

Comparison of energy consumption.

8. Do Air Conditioners improve air quality?

AC systems improve people’s quality of life, providing a more comfortable environment. In addition to achieving the right temperatures and reducing humidity, air conditioning units can renew and filter the indoor air, removing microparticles from the environment, thus making the air you breathe cleaner.

When installing Air Conditioning, look for units with air filtration systems to remove allergens, mould, bacteria, odours and dust from the air. The only brand of split system and ducted air con to have Asthma Council approval is Panasonic with their Nanoe-G technology. 

Proper maintenance and cleaning of your unit will reduce the build-up of dust and mould growth; this also helps keep the unit running more efficiently.

9. What should I know about maintenance before installing Air Conditioning?

After installing the air conditioner, we usually recommend a maintenance service every 6 or 12 months. However, depending on how much you use it and the quality of the appliance, this time may vary.

This maintenance ensures that the unit is working correctly; that the filters are clean to guarantee air quality, and that the system is running at the right gas pressures. As a homeowner, filter cleaning is a must to keep your unit running correctly. For more information, read about the importance of air conditioning service.

10. When, where and who to trust to buy Air Conditioning?

Part of the key when buying an air conditioner is getting good technical advice and back-end support. Many times, to save on costs, people get someone to install it cheaply. However, later they notice that the system is cooling or something else is a-miss. 

All systems take a certain amount of labour and parts to complete the job, it just depends on your installer’s experience and how thorough of a job they do.

Make sure you choose a good air conditioning installer to avoid getting stuck with the wrong system, which can lead to excessive electricity costs and potential warranty issues.

When is the best time to buy Air Conditioning?

Like everything in Australia, peak season means higher prices. When we talk about air conditioning, this refers to summer or mid-winter, when everyone is looking for it.  Installers get really busy during this period, so you might have to wait a few weeks to install your unit.

Most manufacturers offer cash-back promotions once or twice a year in the quieter months to boost sales, that is the best time to buy a system so you can save time and money.

If you’re on the Sunshine Coast, we at Tenmen Electrical offer great prices all year round. Contact us to learn more about our special offers.

Where to buy Air Conditioning?

The best option is to find an air conditioner installer who can take care of the whole process from the supply and installation to the maintenance and repair of the unit, this greatly facilitates the process and can save you a lot of time, money and headaches!

Who should I trust to install my Air Conditioner?

If you live in Australia, look for a licensed air conditioner installer with ARCtick approval. Some traders offer just installation, but I advise finding a company that does all the processes of supplying and installing, so you don’t need to worry about anything.

In addition, I’d recommend looking for an air conditioner installer with an electrical qualification, as your AC needs to be wired around your home or business. In Australia, you can look for Master Electricians Australia certification.

Find an expert in your area who can recommend and advise you on the best options for your specific situation. Unfortunately, no one solution fits everyone.


After reading this guide, I hope you are confident about what to look for when buying air conditioning. Remember that no solution fits all homes or businesses.

To sum up, when installing air conditioning:

  • Make sure you buy the right type and size to guarantee maximum efficiency.
  • Install the indoor unit in the spaces where you spend more time and the outdoor unit in a shady place outside the building
  • Check the energy efficiency rate because this will affect the overall performance and running costs.
  • Choose a unit with inverter technology over a non-inverter one.
  • Choose a unit with a low noise level to guarantee maximum comfort.
  • Look for a certified installer, preferably with electrical certification.
A man in a black shirt standing in front of a van.

About Isaac Jamieson

Electrician, and refrigeration mechanic with over 12 years of experience, Isaac is the founder, director and driving force behind Tenmen Electrical.

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