Understanding the Star Ratings of Air Conditioners


Most people are familiar with the star ratings on our appliances, but there’s a little bit more to consider than just your star rating when choosing an efficient air conditioner. Generally we recommend buying air conditioners with the highest star rating that you can afford, but other things should also be considered. We explain these, and the features of your air conditioner which will determine its star rating in this blog post.


Energy Efficient Ratio

The Energy Efficient Ratio (EER) is one of the fundamental factors used to measure the star ratings of an air conditioning system. This ratio refers to the energy required of the system to move hot air from one space to another. In cooling mode, the heat pump collects internal heat and ‘moves’ it outside. The speed and energy used to complete this, as well as the quality and design of the components used in the air conditioner will influence the EER, and thus the star rating.

Inverter Systems and Star Ratings

Many people are confused when they see that energy efficient inverter air conditioners have a lower star rating than their non-inverter counterparts. The reason for this is that star ratings for inverter systems are based on operation at full load. In practice, most people rarely use or need inverter systems operating at full load.

Why is there no air conditioner with a 10 star rating?

Since 2010, AC systems sold in Australia now have a maximum of 10 stars instead of the previous maximum of 6. There are no systems that currently have 10 stars because the star rating scheme was re-graded to leave room for improvement. (Models under the previous system were reaching six stars but improvements made on new systems meant that efficiency exceeded what qualified as 6 stars.) Note: Systems that achieve 6 stars of less will only display the original 6 star sticker.


If you’re still using a system from decades past, it’s costing you much more money than necessary – especially in the face of rising power bills. Modern systems are far more efficient and the initial cost quickly pays for itself with their reduced operating costs!

For expert advice on your next air conditioner system including the supply and installation of an energy efficient system to work for you, call Greg at Mercury Installations today on (07) 3312 4244