5 common air conditioner habits that drive up your electricity bill this summer

Setting the temperature too low

Many users set their air conditioners to 19–21 degrees Celsius, thinking it will cool the room faster. But Australian energy consultant Alan Langworthy told ABC News this is a costly misconception.

"There are some people that run their air conditioners down at 19 or 20C, 24/7," he said. "They have water running down the windows it's so cold inside. And that is just nuts."

Langworthy said running the unit at 27 degrees Celsius is far more economical than 21 degrees.

Air conditioning compressor units mounted on the wall of a building. Photo from Unsplash

Turning off the unit for short absences

Shutting off the air conditioner every time you leave for a short period might seem like a way to save money, but it could backfire.

Dr. Xiaolin Wang, senior lecturer in mechanical engineering at the Australian National University, said frequent restarts can use more energy and damage the system’s compressor. When the unit is turned off, the room heats up quickly, and the air conditioner must work harder to cool it down again, ultimately using more energy, she explained.

"On-and-off-and-on is not good for the compressor of the air conditioner. So once it's running, I'll keep it running."

If you are going out for under one or two hours, it is better to keep it running, she advised.

Misusing zoning in central air systems

In central air conditioning systems, failing to manage zoning properly can lead to wasted energy. Many users cool the entire home even when only a few rooms are in use.

Experts from Australian air conditioning company Ford & Doonan said using zoning effectively, cooling only occupied areas, can reduce energy use by up to 30%.

Some systems also include smart controls that adjust cooling based on room activity.

Skipping maintenance

Many assume air conditioners can run efficiently without upkeep, but that is rarely the case. Dust and debris can clog filters, coils, and vents, reducing airflow and making the system work harder.

This not only raises electricity bills but also increases the risk of breakdowns. Experts recommend professional servicing at least once a year to maintain efficiency and avoid costly repairs.

Using the wrong fan speed or airflow settings

Running the air conditioner at high fan speed all the time can lead to uneven cooling and higher energy use. Too much airflow can prevent effective humidity removal, while too little may leave parts of the room warm.

Experts advised using auto mode, which adjusts fan speed based on room temperature. High speed can be useful for rapid cooling, but once the room is comfortable, switching to a lower speed helps maintain the temperature more efficiently.