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February 9, 2023

Most Efficient Ways How To Cool The House | Air Conditioning 101

Author: Lance Wiggers

Are you looking for effective ways on how to cool your house? Perhaps you’ve just bought a new place and realised you don’t have adequate cooling, or maybe you need to replace an old, rundown system.

Choosing a new air conditioner is not quite as simple as picking your favourite brand and type. There’s a little more to the process; most importantly, you need to effectively size the air conditioner to the room you want it in or to your home.


How To Cool The House

Choosing the right size air conditioner is important in determining how effectively and efficiently it will cool your space. An oversized air conditioner will waste energy to cool a smaller area, while an undersized air conditioner will fail to adequately control your home’s temperature. To properly size up a new air conditioner, you need to consider a number of factors, including your home’s size in square metres, the location of your air conditioner, your insulation, and the room’s sun orientation.

How to choose what size aircon I need?

There are three main ways to calculate, or estimate, the right size for your air conditioner, including using a manual formula, using an online calculator, or hiring a professional to perform a load calculation.

The size of an air conditioner is measured in kilowatts, kW, which measures how much wattage is required to run the unit.

Calculating your aircon size

If you’re still sitting there confused on how to calculate aircon size for the space you want to cool, but everything you look up isn’t helping, here’s a quick and simple step by step to help you out.

To manually determine the size of your unit, you will need to complete a few steps:

  • Step 1: Determine what area you wish the air conditioner to cool. This could be an open-plan living space or a single bedroom.
  • Step 2: Determine the square metre size of the floor area. You can do this roughly by multiplying the room’s length by the width.
  • Step 3: To find the kW size of the air conditioner you will need, multiply the square metre result by 0.1-0.2, depending on how effective the room’s insulation or how much sun exposure there is. If the room is poorly insulated or experiences a lot of direct sunlight, then make the figure closer to 0.2. If the room is well insulated and as exposed, multiply the room result by 0.1 to find the right air conditioner size.


For example, a well-insulated room, which is 25m², would need a 2.5kW air conditioner, whereas a very poorly insulated room may need a 5kW air conditioner. An average household room would use a multiplier of 1.5, meaning you will need a 3.75kW air conditioner. This method is a rough estimate, as it does not consider a room’s unique features, particularly its height. For example, a room with high ceilings would require a larger air conditioner to cool the space.

Some online tools can provide more specific results by considering more variables such as location, size of the room, and insulation effectiveness. By entering the information, you can receive an immediate understanding of what you could need.

Hiring a professional

Hiring a professional to perform a load calculation is a great way to get a specific understanding of your home’s needs. They can take into account all the relevant information, including the space size, the home’s orientation, and the ceiling height.

They can also use more specific information that basic calculations will miss, such as the number of windows and doors and the current cooling systems in place. They can even determine how much heat your appliances will generate.

Once they have this information, they will typically use advanced load calculation softwares to determine the specific size and, in some cases, unit model you need. This will usually be determined by finding the required British Thermal Units (BTUs). A BTU is an imperial system measurement that determines how much energy is required to heat or cool one pound of water by one degree Fahrenheit.

They will then convert this metric into a kW size. While this may be a more laborious solution than an online tool, in the long run, it can help to reduce your energy bills by finding the correct size of air conditioner for your space.

Air Conditioning Professionals

How to cool a small space?

A small space, such as a guest bedroom, or study, will require a smaller air conditioner. Smaller models are usually between 1.5-2.5kW. A split system air conditioner is best suited for a small room, as these units are relatively compact and simple to install.

How to Cool a Small Space

How to cool a large space?

A larger space, such as an open plan living area, or a master bedroom with an ensuite and walk-in wardrobe, would require a larger capacity air conditioner. Depending on the square meterage of the room, the air conditioner capacity would need to be between 4-10kW. A split-type aircon would work well in a large room; however, a ducted refrigeration air conditioning system might be better suited if you are looking for whole-home cooling.

How to Cool a Large Space

Are there air conditioners which can cool an entire building?

Split system air conditioning, usually installed on a home’s internal wall, is great for cooling a variety of spaces, but even the largest split system will struggle to cool the entire home. Furthermore, having multiple split systems may not be an efficient use of energy and end up increasing the running costs of cooling your home.

Instead, a ducted air conditioner may better suit your needs if you require whole-home cooling. A ducted air conditioner is typically installed in the roof or, in some cases, under the floor and uses a series of ducts to push cool air through a building. A centralised thermostat and air conditioning unit then cools the entire home.

These systems are typically more expensive and have a large energy requirement, often exceeding 10kW. However, they can be far more efficient than split systems if used regularly. They can also provide a greater level of control as most systems will allow you to selectively cool rooms to different temperatures and schedule when and where it should be active.

Access the best cooling solutions with iBreeze

If you’re looking for new air conditioning and are unsure what size, brand or type to install in your home, contact iBreeze today. We can help assess which size is best for your needs, and find the perfect air conditioner model to help you escape the summer heat. Whether you wish to install a small unit in your study or need a more comprehensive cooling system to cool an entire office floor, we can help you find a cost-effective and efficient solution.

Lance Wiggers
Lance Wiggers is the founder and managing director of iBreeze, having started the company back in 2016. His expertise spreads across air conditioning services, solar power and wood heating to provide customers with a more comfortable living or working space. Lance's tailored approach means he always chooses the solution best for your specific situation. You might have the pleasure of dealing with Lance as your first point of contact when you enquire with the iBreeze team!
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