What Drives Your Air Conditioning Running Costs

Two homes can run the same air conditioner for the same hours and still get very different power bills. That is because running cost comes down to a handful of factors: some about the system, some about your home, and some about how you use it. Here is what actually moves the number, and where the biggest savings sit.

It's a big share of your bill. Heating and cooling make up around 40% of the average Australian household's energy use, and up to 50% in hotter climates. [1] That is why small changes to how you run your system show up clearly on your bill.

The temperature you set. This is the lever with the fastest payback. Setting your system one degree lower for cooling, or higher for heating, can add around 10% to your running costs for each degree. [3] Aiming for 25 to 27 degrees in summer and 18 to 20 in winter keeps you comfortable without overworking the system. [3] If that feels too warm or too cool, 23 to 25 in summer and up to 22 in winter is still reasonable, just expect each degree to add around 10% to your running costs.

How efficient your system is. Every non-ducted air conditioner sold in Australia carries a Zoned Energy Rating Label, which shows its efficiency across hot, average and cold climate zones. [2] More stars means less electricity for the same output, so a high-rated model can cost noticeably less to run than an older or budget unit. [2]

Reverse cycle is a heat pump. A reverse cycle air conditioner does not burn energy to make heat, it moves existing heat from outside to inside, which is why models on the Australian market run at 300 to 600% efficiency. [1] So despite a common assumption, reverse cycle is usually the cheapest way to heat a home, far more efficient than a plug-in electric heater. [1]

The system type. Ducted systems condition the whole home and lose some energy through the ductwork and a larger fan, so they generally cost more to run than a wall-mounted split serving one area. [1] Matching the system to how much space you actually need to condition keeps costs down.

Whether it's sized right. An undersized system runs flat out and struggles to reach temperature, while an oversized one costs more to buy and to run. [2] Correct sizing is the foundation of efficient running, which is why it comes from a proper assessment rather than floor area alone.

How much of the home you condition. Conditioning empty rooms is wasted energy. Closing doors to unused rooms, or using zoning on a ducted system to cool only the areas in use, cuts the load your system has to carry. [1]

Your home's thermal performance. Draughts, poor insulation and unshaded windows all let conditioned air escape and outside heat pour in, so the system works harder to hold temperature. [1] Sealing gaps around doors and windows and shading glass reduce that load before you spend a cent on running the unit. [1]

How well it's maintained. A clogged filter restricts airflow and forces the system to use more energy for the same result, so regular filter cleaning lowers consumption. [2] It is one of the simplest ways to stop running costs creeping up across a season.

When you run it, and your tariff. Your cost per kilowatt hour depends on your electricity plan, and many plans charge more during peak afternoon and evening hours. [3] If you are on a time-of-use tariff, running or pre-cooling the home outside those peak periods lowers what the same usage costs. [3]

Understanding these drivers is the first step. If you are weighing up a new system, or want one sized and set up to run efficiently, AC Wise connects you with vetted, licensed professionals across Australia.