What do star ratings mean and are they accurate?

Star ratings provide an easy way of comparing the energy efficiency of different models that perform a similar task.  In the case of air conditioners, a model’s efficiency is the amount of cooling (or heating) capacity (output) per unit of energy it consumes (input).

However, looking at the stars alone is not helpful, as the performance of a large appliance that is capable of heating and cooling a 200 square metre house can’t be compared to a small product designed for a small bedroom. Therefore the cooling and/or heating capacity required to heat or cool the room/house needs to be determined before energy efficiency is considered.

What about ‘Inverter’ technology?

The most common type of Air Conditioner, an inverter model means that the compressor is powered by a variable speed drive -‘inverter’- which enables the compressor to run at a range of speeds from slow to fast, to match the output required.  Previously the majority of products had fixed speed compressors that could only run at a constant speed, and in order to vary their capacity they have to switch on and off at different intervals.  This means that their efficiency does not vary significantly when they run at part load.

Inverter systems however, are a sophisticated piece of technology that improve the performance and energy efficiency of air conditioners under normal use

This is achieved by reducing the continuous compressor output, which increases the efficiency of the refrigeration system (as the apparent size of the condenser and evaporator is larger)

So, while these systems may look less efficient on their Star rating at full load, they tend to be very efficient at part load operation, which is a more common mode in a typical household.  In saying that, work is currently underway to consider changing the rating system to take into account this efficiency.

If you are unsure what size, rating and type of Air Conditioning to install, please contact us for a free quote and some helpful advice today on 1300 222 747.

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