Whether it is consistent heating or cooling you require in your home or office, a great choice is a reverse cycle air conditioner, because it offers you a simple to use discreet, reliable and energy efficient temperature control throughout the residence.

Aesthetically, it is also appealing as ducted systems are relatively unobtrusive with the conditioned air being disbursed through ducts hidden in the roof space and connected to a ceiling register in each room

Ducted reverse cycle air conditioners utilise 2 main parts, an indoor unit and an outdoor unit.

The indoor unit works similar to a fan, it will draw air from the “return air” box and it will blow air out through your vents.

The outdoor unit is where the magic happens, it changes the state of the refrigerant from a liquid to a gas, depending if you require heating or cooling. The gas will then either heat or cool the refrigeration pipes which will run through the indoor unit, providing your heating or cooling. The outdoor unit can be noisy so it is advised to keep them away from bedrooms and neighbours if possible.

Ducted reverse cycle air conditioners are designed to control the air temperature with as least noise as possible inside the home while also providing an even coverage of a home or office. They are suited properties which require multi room air conditioning.

Housing Zones Diagram

How do I calculate the size of air conditioner that I will need?

The three main ways to calculate your air conditioning needs are

  • With a formula
  • By using an online calculator
  • By getting a professional to visit your home to calculate things precisely


Using a formula to calculate your air conditioning needs

Using a formula to estimate your air conditioning needs is quick and easy, but it’s also very rough and doesn’t take many important factors outlined into consideration. It’s a good way to get a general idea of your needs, but if you’re after a truly accurate understanding it’s probably best to use one of the other two methods before you commit to anything.

To estimate the amount of air conditioning you will need for your daytime living area, you will first need to find out its area in square meters (m2). You will need to multiply the length (L) by the width (W) (LxW) for each room individually.


Once done, you will need to add them all together to get your total living space in square meters (m2). You don’t need to include areas that are not living spaces, i.e bathrooms, garage, pantry.

Last step to help with sizing your unit is determining the energy requirement. This will vary depending on your ceiling height. The measurement you had done in the previous step would be similar to a piece of paper, it is only a flat area. We need to condition the air in the whole space between the floor and ceiling. The larger that space is, the more energy required.

Below we have the energy requirements for 3 common ceiling heights in Australia

  • If your ceiling is 2.4m high, you will need to multiply the day time living area (m²) by 0.15 (kW)
  • If your ceiling is 2.7m high, you will need to multiply the daytime living area (m²) by 0.16 (kW)
  • If your ceiling is 3m high, you will need to multiply the daytime living area (m²) by 0.175 (kW)

Once we are sure what our ceiling height is, we can now multiply the energy consumption by the floor area

For a house with a daytime living area of 110m² and a height of 2.4m, the calculations would be:
110m² x 0.15 kW = 16.5kW

A 16.5kW unit is roughly the right size for this house.

Using an online calculator to figure out your air conditioning needs

If you use an online calculator, it will give you a more accurate estimate than the above method, but you will also have to take more factors into consideration.

Using a professional to figure out your air conditioning needs

The most accurate way to find out the air conditioning capacity that you will need for your home is by getting a professional to come in and calculate it. They have years of experience, which they can use to get the most accurate estimate of your air conditioning needs. They will take each factor into consideration and help to make sure that you have the perfect sized air conditioner for your home.

Contact us today to have a professional out to provide you a quote on system to suit your needs