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Air Conditioners

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Air conditioners provide a space conditioning (cooling only or heating and cooling) service to improve the thermal comfort of an indoor space (such as a room, entire home or larger complex).

Air conditioners are also used in commercial and industrial buildings such as offices, shopping centres and manufacturing premises. 

Residential air conditioners (also referred to as heat pumps particularly in New Zealand), were first required to carry an energy label in 1987 and have been subject to Minimum Energy Performance Standards (MEPS) since 2004.

Larger three phase air conditioners (that are normally used in non-residential situations) have been regulated for MEPS since 2001 and have a voluntary labelling scheme.

Types of air conditioners

There are two main types of air conditioning products on the market:

  1. refrigerative products (using the vapour compression cycle)
  2. evaporative products.

Refrigerative products have been the main focus of the E3 Program (and are the focus of this page), however some research has been undertaken on evaporative products and they may be considered in the future.
Refrigerative air conditioners can supply a cooling only service, and reverse cycle products are capable of heating as well as cooling. The main types of products are as follows:

  • Split system (non-ducted): The most common type of household air conditioners. These products have an outdoor unit that houses the compressor and condenser, and an indoor unit that is commonly mounted on a wall. They can range in size to suit a small bedroom, to much larger products that could suit large open plan living areas.

  • Window/wall units: These products contain all parts in a single unit (rather than having a separate outdoor and indoor unit). They are installed either through windows or can be mounted into walls (where the back of the unit will be outdoors). They are typically less efficient, but cheaper to purchase and install than split systems and are suitable for cooling or heating single rooms.

  • Ducted systems: Ducted products can provide heating and cooling for an entire home or premises, delivering warm/cool air via ducts positioned in various rooms. These systems can be zoned so that only certain areas are being conditioned (for instance only living areas during the day). Two types of systems are: 

    • domestic ducted units are split systems that consist of a single outdoor unit connected to an indoor unit installed in the roof cavity or under the floor

    • commercial ducted units tend to consist of a single unit on the roof or next to a wall and are connected to the building through ductwork only. They are available in single phase and three phase power and energy labelling is voluntary for these products.

  • Multi-split systems: Multi-splits consist of multiple indoor units connected to a single outdoor unit. These can allow for different temperatures in different rooms.

  • Double/triple split system: An increasingly uncommon configuration that consists of a single outdoor unit and two or three indoor units that cannot be controlled individually.

  • Portable products: Like window/wall units, portable air conditioners are unitary systems. However, they are contained entirely within the space to be conditioned (i.e. a room) and air is drawn from indoors, cooled and then expelled outside via a single duct. These products are not currently regulated – for more information see Portable air conditioners.

Solar air conditioners

Many types of solar air conditioning technologies exist, although most of them are unlikely to be found in the domestic market. Some examples include:

  • Adsorption chillers use heat (e.g. from solar thermal collectors or waste heat from other processes) to evaporate water in a vacuum which absorbs heat from its surroundings. Other materials can also be used. These tend to be used alongside large industrial processes to utilise waste heat and are sometimes encountered in commercial buildings as part of a cogeneration/trigeneration system.
  • Absorption chillers use heat (e.g. from solar thermal collectors or waste heat from other processes) to drive the refrigeration cycle. Familiar applications include kerosene or gas fired fridges. They are also used as part of cogeneration/trigeneration systems.
  • Solar desiccant cooling uses desiccant material to absorb moisture (humidity) from the air to help with cooling. Solar heat is then used to dry the desiccant material in a continuous process. The CSIRO has successfully deployed this technology commercially.
  • Solar cooling using ejectors uses heat to create a thermally driven compression process. Many researchers are looking at ways of making this process economical for commercial applications (for instance, see the Australian National University).

None of the above solar cooling technologies are covered by the E3 program. However there are two types of ‘solar’ air conditioners that can be found on the domestic market and are covered by E3 regulations.

  • Normal electrically driven domestic air conditioners of the vapour compression cycle that use photovoltaic (PV) panels to provide electricity directly to the air conditioners’ electrically driven compressor. This PV generated electricity offsets the amount of mains electricity that is required.
  • Normal electrically driven domestic air conditioners of the vapour compression cycle that use solar thermal collectors to add heat to the refrigeration cycle (although some companies claim this process helps remove heat from the refrigeration cycle).

E3 tested these last two types of solar cooling technologies, the results of which can be seen here. While the report found that the PV equipped products worked with some reservations, the solar thermal products all failed to meet Minimum Energy Performance Standards (MEPS). Further, the addition of solar thermal collectors reduced the efficiency of these products, reduced the cooling they provided and, in some cases, also reduced the heating provided. Solar thermal air conditioners work better without the solar thermal boost operating.

Regulatory requirements for air conditioners

Single phase non-ducted air conditioners for household use are regulated for energy labelling in Australia and New Zealand. All three phase and single phase ducted air conditioners up to 65kW cooling capacity are regulated for Minimum Energy Performance Standards (MEPS). Manufacturers can choose to label three phase and ducted air conditioners, but this is not mandatory. MEPS details are shown on the air conditioner MEPS page.

What are we working on?

Air conditioner regulations and labelling requirements will be updated following COAG Energy Council’s agreement to the Regulation Impact Statement on air conditioners in December 2018.

Refer to Current Work for more detail.

About air conditioner labels

Domestic single phase, non-ducted air conditioners must carry an Energy Rating Label. Labels on ducted systems are voluntary, so not all products will have one. You can still view their energy efficiency performance on the GEMS Registration Database. In manufacturer’s literature they may refer to energy efficiency ratios (EER) and co-efficients of performance (COP) which are the efficiency ratings for cooling and heating respectively. They are simply a ratio of the output (capacity) divided by the power input. They may also mention an annualised version of these metrics (AEER and ACOP). These are virtually the same thing, but deduct standby power. The Energy Rating Comparison Tool provides the power input and outputs for all products, even unlabelled ones. This allows you to calculate the EER and COP yourself. You can then compare these and choose a model with a higher EER/AEER and/or COP/ACOP.

For non-ducted household air conditioners, you can still compare models online or using the free Energy Rating app, but you can also use the label. Air conditioner labels are a little bit different to labels for other household products and have some product specific information on them.

The stars

Just like on other appliances, air conditioners are given star ratings, blue for their cooling function and red for their heating function (unless the appliance is a cooling only device, and then it will have the blue stars only). The more stars a product has, the more efficient it is. Air conditioners can currently be rated up to 10 stars. If a product is rated at 6 stars or less, it will not show the extra star ‘super efficiency rating’ band. You can see on the above example that this unit is rated 7 stars for cooling and 4 for heating, so only the cooling star arch has the additional coronet.

You can compare the efficiency of different products using the stars, however you must compare products of the same or similar size. You can find this in the middle of the label, in the capacity output box.

Capacity output and power input

The capacity output figures on an air conditioner label will let you know the amount of cooling and heating the model can produce. These are the figures you should check are of similar value when comparing star ratings. See size matters for information about the importance of choosing the right sized product.

The power input shows you how much power is required to produce the heat or cooling shown in the capacity output box. If two products have the same star rating and same capacity output you can see which product is more efficient by choosing the one with the lower power input.

Some labels may also have a separate declaration within the heating output and input box, as shown above. This number will show the heating output capacity of the product when tested at 2 degrees Celsius. The main figure is based on testing at 7 degrees. When outside temperatures are below approximately 5 degrees, outdoor units can begin to ice up and this will impact on the capacity of the unit (i.e. the amount of space it can heat). This declaration is voluntary and won’t be found on all models. However if you live in an area that regularly has temperatures below 5 degrees, it can be worth looking for this figure or asking your retailer or installer.

Variable output compressor

This box shows whether the unit has a variable output compressor, commonly known as an ‘inverter’ air conditioner. These units are able to vary the speed at which they operate to suit conditions, so on a mild summer day they won’t have to work as hard as when it’s 40 degrees outside. Traditional single speed air conditioners, which are less common today, simply turn on and off as set temperatures are met.

Demand response capability

The Demand Response (AS4755) section of the label refers to the appliances’ inbuilt capability of participating in a voluntary peak electricity demand management program. An example of such a voluntary scheme is Energex’s PeakSmart air conditioning program(link is external). This feature is only relevant to these types of voluntary programs and will not affect normal operation.

  • Mode 1 means the appliance is capable of being turned off and back on.
  • Mode 2 means the appliance is capable of being turned down by 50%.
  • Mode 3 means the appliance is capable of being turned down by 25%.
drawing of Australian map with the words climate changes the efficiency of this appliance

Zoned Energy Rating Label

The energy efficiency and performance of certain appliances can be impacted by where they are installed (location) and other factors such as usage patterns and climate variations, including air temperature, water temperature, frosting, humidity and cloud cover. The EEAT is examining a move to a zone-based energy efficiency labelling system for some products or product categories.

Size matters: Air conditioners

When considering purchasing a new air conditioner, the most important initial step is to ensure you select a suitably sized unit. Unlike other products such as televisions, where the size of the product is obvious, air conditioners typically look similar despite having wide ranges of heating and/or cooling capacities. Sizing for air conditioners is provided as a kilowatt (kW) capacity output figure (not to be confused with the power input, which is the amount of power required to produce the listed cooling and/or heating output) and you can find this on the energy rating label, as well as on the manufacturer’s product literature.

There are many different elements within your home that will impact on the size air conditioner you’ll require. These include (but are not limited to):

  • Whether you are looking to heat/cool a single room, a larger space or your entire home;
  • Size of room/home (including ceiling height);
  • External wall materials;
  • Insulation levels; and
  • How many windows you have, their glazing, shading and orientation.

Because of all these factors, it’s best to have a professional advise you on the size air conditioner to look for. There are also free online tools you can use to give yourself a rough idea, for instance the Australian Institute of Refrigeration, Air conditioning and Heating (AIRAH) offer the ‘Fair Air’ calculator.

Another element to consider is where you live. If you live in a cool climate, or where in winter temperatures are regularly below 5 degrees Celsius, it’s important that the unit you choose is able to cope in these conditions. Some models’ capacity will reduce at these times so you may find it unable to heat your space sufficiently, while others are able to continue to meet or exceed their capacity. Some manufacturers will test their products at a colder temperature and provide the capacity output for 2 degrees Celsius. This information isn’t always easy to find though, so check with your retailer or installer to see if they can assist.

Undersized units will have to work harder to heat or cool your room, and may be unable to reach and maintain your preferred temperature. Oversized products will typically be less energy efficient and they’re likely to cost more upfront as well.

Ensuring the product you have selected is an appropriate size will mean you’ll remain comfortable in your home and not use more energy than necessary.

Air conditioner FAQs

What are Star Ratings?

Star ratings have been developed to provide an easy way of comparing the energy efficiency of different models. In this context, energy efficiency is defined as the ‘energy service per unit of energy consumption’. It is a simple and fair way of comparing the energy consumption of products 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 cannot be compared to a small product designed to condition a small bedroom. This means that the cooling and/or heating capacity required to heat or cool the room/house needs to be determined before energy efficiency is considered.

For most products covered by the E3 program, the standard star rating system has a minimum of 1 star and a maximum of 6, shown in half star increments. Various algorithms or equations have been developed to rate the least efficient products at around 1 star. For air conditioners, products can receive up to a maximum of 10 stars.

See the About Air Conditioner Labels for more detail

How are star ratings calculated?

The star rating for air conditioners is determined differently to other appliances. For air conditioners, the measure of energy efficiency is the Energy Efficiency Ratio (EER) for cooling and the coefficient of Performance (COP) for heating. The EER and COP are defined as the capacity output divided by the power input. The Star Rating Index is calculated on the measured values for energy and capacity during a rating test, rather than the nameplate or rated values.

The current star rating system is now based on an annual efficiency calculation (AEER and ACOP) which includes any non-operational energy consumption such as standby power, and power consumption of crank case heaters (where present). This gives a more accurate representation of energy efficiency across a year.

What types of air conditioners are not required to carry an energy rating label?

The following air conditioners are not currently required to carry an energy rating label:

  • evaporative air conditioners,
  • ducted air conditioners (these may carry the label on a voluntary basis),
  • three phase air conditioners (these may carry a label on a voluntary basis but are unusual for the residential sector),
  • multi-split air conditioners (units with several separate indoor units each with a separate control),
  • air conditioners intended purely for commercial applications
  • single exhaust duct portable air conditioners.
How do air conditioners work?

The system uses a refrigerant (which exists as a gas at low pressure and as a liquid under compression) which is compressed and liquefied, allowed to cool in a condenser, and then allowed to expand in a controlled way (through an expansion valve) to become a gas in an evaporator (the expansion is accompanied by a strong cooling effect). In this operation the condenser becomes warm and expels heat.

The principle is the same as that used in a normal refrigerator which “moves” heat from the inside of a refrigerator to the outside. In the case of an air conditioner when in cooling mode, the heat is removed from the room being cooled and pushed outside through the refrigeration system. Similarly, if the unit can operate in “reverse” (called heating mode or reverse cycle), the process runs backwards and the energy is collected from outside and moved inside to the room being heated. In most cases, air conditioners are more efficient when operating in heating mode as the energy used to compress the refrigerant can also contribute to the net heating output.

How can an air conditioner be more than 100% efficient?

The system uses a refrigerant (which exists as a gas at low pressure and as a liquid under compression) which is compressed and liquefied, allowed to cool in a condenser, and then allowed to expand in a controlled way (through an expansion valve) to become a gas in an evaporator (the expansion is accompanied by a strong cooling effect). In this operation the condenser becomes warm and expels heat.

The principle is the same as that used in a normal refrigerator which “moves” heat from the inside of a refrigerator to the outside. In the case of an air conditioner when in cooling mode, the heat is removed from the room being cooled and pushed outside through the refrigeration system. Similarly, if the unit can operate in “reverse” (called heating mode or reverse cycle), the process runs backwards and the energy is collected from outside and moved inside to the room being heated. In most cases, air conditioners are more efficient when operating in heating mode as the energy used to compress the refrigerant can also contribute to the net heating output.

How does an air conditioner compare to a normal electric heater?

Reverse cycle air conditioners are substantially more efficient at heating than standard electric heaters (bar heaters, convection or radiant heaters).

As an example, for all domestically sized air conditioner products, minimum energy performance standards ensure that the least efficient product available is approximately 300% efficient – i.e. for every 1kW of electrical input it produces 3kW of heat output. This would be a 1 star product. For ducted air conditioners that are not required to provide a label, manufacturer’s literature should refer to its coefficient of performance (COP) or annual coefficient of performance (ACOP), which will start at around 3. The best reverse cycle unit currently on the market has an ACOP of 5.76 which corresponds to 7 stars.

Standard electric heaters, on the other hand, have an efficiency of approximately 100% - so for every 1kW of electrical input they can produce around 1kW of heat output.

Are evaporative coolers more energy efficient than conventional air conditioners?

As a rule, evaporative air conditioners use less energy than an equivalent ‘vapour compression’, or refrigerative type of air conditioner. However, a fair comparison of these products is difficult. Evaporative air conditioners rely on the evaporation of water to cool the air (evaporation is accompanied by a cooling effect) and so increase the humidity in the cooled space. These types of systems are really only effective in drier climates. Unlike conventional air conditioners (which remove moisture from the cooled space and work best in a sealed room), evaporative air conditioners require a large volume of fresh air to pass through the house, so ventilation to allow internal air to escape is essential. Evaporative air conditioners can also consume substantial volumes of water, which may be an issue to consider for homeowners.

What is an ‘inverter‘ air conditioner?

An inverter model means that the compressor is powered by a variable speed drive or ‘inverter’, which enables the compressor to run at a range of speeds from slow to fast, to match the output required. These are now the most common type of air conditioner. Previously the majority of products had fixed speed compressors which could only run at a constant speed. In order to vary their capacity they have to switch on and off at different intervals. Inverters are a sophisticated piece of technology which improve the performance and energy efficiency of air conditioners under normal use. Inverter models are marked in the GEMS Registration Database for air conditioners.

If ‘inverter’ type air conditioners are more efficient, why don’t they get higher star ratings?

For fixed speed air conditioners, efficiency does not vary significantly when they run at part load – reduced load output (heating or cooling) is achieved by the unit turning on and off through the thermostat or temperature control system.

Inverter units use a variable speed drive in the motor system that drives the compressor. While these systems may look less efficient at full load (i.e. their star rating at rated capacity, which is the rating on the energy rating label), they tend to be very efficient at part load operation, which is a more common mode in a typical household. 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).

Performance does vary between models, so the actual part load performance of inverter units should be sought from manufacturers. Inverter units are now marked on the registration database and part load efficiency data is also available for some inverter models. Work is currently underway to consider changing the rating system to take into account this efficiency.

What does Power Input (also called Comparative Energy Consumption or CEC) mean?

The energy consumption or power input of an air conditioner is measured under conditions specified in an Australian Standard. Because the heating and cooling requirement is affected by climate and this varies substantially across Australia and New Zealand, an annual energy consumption figure is not shown on the energy label. Instead, the cooling and/or heating Output and the Power Input is shown on the energy label at rated capacity (the units on the label are in kW which is the same as kWh/hour). To work out the likely annual energy use will require information on the climate and other factors such as occupancy (hours that cooling is required) and building shell performance (insulation, glazing, orientation etc). It is important to note that under normal usage, the air conditioner will spend a significant amount of time at less than its rated capacity – in terms of efficiency this is important for variable output models which can have higher efficiency under part load conditions.

What does Capacity Output mean?

The measure of energy service for an air conditioner is the rated cooling and/or heating capacity of the air conditioner, usually specified in kilowatts (kW) (some product brochures use British Thermal Units or BTUs, although this is not common). Some retailers may use compressor ‘horsepower’, although this has no meaning in terms of the unit’s capability. These rated values are as declared by the manufacturers under the test conditions defined in the Australian/New Zealand Standard (which is based on the relevant international standard). The heating capacity of a reverse cycle air conditioner is the heat that can be put into a room. Similarly, the cooling capacity is the heat that can be removed from a room. The cooling capacity is made up of the sensible component (usually the majority of the capacity) which relates to the actual temperature reduction (cooling) of the air, plus the latent component, which is a measure of the de-humidification effect of the indoor air. Latent cooling capacity is sometimes expressed as moisture removal capacity in litres or kg of water per hour (1 kg per hour of moisture removal is equal to 683 Watts latent capacity).

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