Energy efficient cooling: do split-systems come out on top?

With a rising cost of living, smart decisions around heating and cooling your home can have a positive impact on your monthly bills.

Your Home
8 min read
Australian weather can be extreme – and summer temperatures continue to reach record levels. But winters can be bitingly cold too, which makes both heating and cooling a necessity for year-round comfort.

Depending on where you live, cooling and/or heating can account for 20% to 50% of the energy used in your home. To keep your household bills down and environmental impacts low, it’s now even more important to think about cooling your home as efficiently as possible.

But here’s something that might surprise you. For many years it’s been said that gas is the more cost-effective way to heat your home. However, with improvements in technology and increasing gas prices, this is no longer always the case. An energy-efficient, reverse-cycle and split-system air conditioner can be your most efficient year-round option – and here’s why.

A cost-effective solution

High efficiency, reverse-cycle split-system air conditioners will save you from the blistering heat, and they can be the most efficient way to keep you warm on cold winter nights. So, keep this in mind if you’re choosing a new aircon system this summer.

What is a reverse-cycle split-system air conditioner?

A reverse-cycle air conditioner is one which both heats and cools since it has heat pump technology embedded within it.

A split system is one of the most popular types of air conditioning available because it’s both convenient and efficient. A split-system separates the inside and outside units. The inside is sleek and quiet, holding just the cooling coil, long blower and an air filter. Meanwhile, the outside unit holds the compressor and fan – which keeps any noise out of your living space.

What makes reverse-cycle air conditioners efficient?

Conventional heaters have to generate their own heat energy, such as burning gas. But a reverse-cycle air conditioning system absorbs the heat from the air outside and uses that energy to heat the air inside, making it very energy efficient. And it doesn’t need to be warm outside either – this technology works the same way even in freezing conditions. It’s the opposite of how your fridge works.

A reverse-cycle air conditioner can reach 300–600% efficiency, which means that it can take one unit of thermal energy and turn it into three to six times as much heating or cooling energy. Under mild conditions, some products can achieve efficiencies of over 1000%. If you set your air-conditioner temperature at roughly 8 degrees Celsius lower than the outside temperature, every degree lower will increase running costs by around 10%. Or in other words keep your air conditioning at around 23 – 24 degrees in summer. Any degree higher in winter or lower in summer increases usage by 10%.

Woman in living room with laptop

Gas options, on the other hand, are becoming more expensive to run as the price of gas increases – plus, they lack the efficiencies of the latest air conditioning technology. A University of Melbourne study found that reverse-cycle heating was cheaper to run than gas heating in every city tested. And while gas heaters tend to have lower upfront costs than reverse-cycle air conditioners, the temperature can’t be controlled as precisely.

Not all air conditioners are created equal

A split system is just one of your many options when investing in an air conditioner. The option you choose will depend on your priorities and the spaces you’re heating and cooling. Below you’ll find types of air conditioners to consider:

Evaporative coolers

Evaporative coolers work by blowing air over a film of water on a filter or sponge, cooling the sponge and the air through the process of evaporation. Outside air is drawn through the evaporative unit (generally on the roof) and cooled. This cool air is then forced into the house, which pushes the hot air out through open windows and doors. This type of cooling unit is only suitable in low-humidity areas that don’t experience extreme heat (over 35 degrees Celsius).

Ducted air conditioning systems

A ducted system is designed to cool and heat an entire home. They have an outdoor unit and ducting that is usually installed in the ceiling or under the floor. Air ducts run from the outdoor unit, generally through channels in the ceiling, and then into each room. This can be an expensive option to both install and run, but it can be a cost-effective way to heat or cool a large house. Think about whether a ducted system or multiple split-systems would suit your needs better.

Window and wall air conditioning units

A window unit is a single box installed in a window or less typically, through an external wall. For smaller spaces of up to 50 square metres, these can be useful and affordable options, especially where a split system is unavailable (for example in rental properties).

Smaller units can be plugged into a normal powerpoint, but larger ones may need additional wiring. These units aren’t as energy efficient as split systems but can be a viable alternative with lower up-front costs. However, as their energy efficiency rating is lower, they will have higher running costs.

A wall unit is made up of an external compressor unit and an internal unit mounted on the wall. Usually, one wall unit is installed in each room in the house. There is a range of products in the market so be sure to choose the ones with the highest star rating to keep your heating and cooling bills under control. Wall units are also a great way to match installation costs according to your income (i.e. you don’t have to install them all at once).

Reverse-cycle air conditioners are not only great at keeping your home at comfortable temperatures year-round. Chosen well, they can be an efficient and cost-effective option that can help you reduce your power bills and environmental footprint.

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