How much does it cost to run the air conditioner over Summer? (2024)

Air conditioners tend to have a higher advertised wattage than heaters, but thanks to heat pump technology they can actually be cheaper to run.

Air conditioners, be they split-cycle, or portable, have an input power wattage and a cooling capacity. Although both are measured in watts, only the input power dictates how much power the appliance has to pull from the grid. The cooling capacity indicates how efficiently the air conditioner can use the input power, and how large of a space it can handle. On average a split-cycle air conditioner will run at around 300% efficiency, meaning that each kW of power can cool around three units of heat. These numbers vary depending on the make and model, but while an air conditioner might have a cooling efficiency of 4500w, it may only use 1800w of power.

To find out how much your air conditioner will cost you to run, you'll only need to know the input power wattage. The higher this number is, the more expensive the device will be to operate.

Based on last year's average electricity pricing across the country ($0.14kW/h), it can cost as low as $92.74 to run an efficient portable air conditioner for the season. Naturally that number will change depending on a bunch of factors like how much you pay for electricity, the aircon model, and how long you run it for. In order to determine exactly how much your air conditioner will cost you to run, you'll need to know;

• The input wattage for your device
• Your kw/h usage charges from your electricity company (and any peak charges)
• How long you plan on running your air conditioner for each day

When you have these numbers you simply need to multiply your Kw/h cost, by the input wattage to determine how much that device will cost per hour. From there you can multiply that number by how many hours per day you’ll likely use your heater, and again by how many days across summer (92). The formula looks like this;

For the most part portable air conditioners aren't particularly energy efficient to use. Many, especially cheap units, tend to have a 100% efficiency, meaning the input power is the same as the cooling capacity. This means that what you see, is what you get. It isn't neccessarily a bad thing. It makes it easier to pick out a unit, and there are still plenty with a low enough wattage to not entirely break the bank. 

In saying that, there are portable air conditioners with surplus cooling efficiency similar to split-systems. Dimplex makes some excellent units that run at over 250% efficiency, and will only set you back around $0.25 per hour to run, plus they're pretty affordable to buy outright. On the other end of the spectrum, there are some where the input power outdoes the cooling capacity. Avoid these at all costs.

Split cycle air conditioners might be more expensive in the short term, but they can be surprisingly affordable to run over their lifespan, especially in larger spaces. While the cost per kW remains the same regardless of the type of cooling device, split cycle aircons can cool air 3-6 times more efficiently and therefore require a lower wattage to service a larger space. This ultimately means a 3.2kW system could perform as effectively as a 9.6kW, so it won't need to be run for as long to have the same impact on a space. 

At the lower end, a split cycle with 3.2kW input power will cost around $0.45 per hour to run, but larger systems can set you back over $1 per hour.