Blog > 5 Common Air Conditioner Mistakes That Are Costing You More on Your Energy Bill

17/02/2025

5 Common Air Conditioner Mistakes That Are Costing You More on Your Energy Bill

With over 40 years in the industry, we’ve seen countless factors that can cause an air conditioner to consume more energy than they should. Many homeowners unknowingly make simple mistakes that can lead to higher energy consumption and costly electricity bills. If you’re looking to reduce your running costs while keeping your home comfortable, it’s crucial to avoid these common mistakes. Let’s explore five of the most frequent air conditioning mistakes that could be driving up your energy costs and how you can correct them.

Ignoring Regular Servicing and Maintenance

One of the biggest and most common mistakes homeowners make is neglecting regular air conditioner servicing. Many people assume that their air conditioning system will keep running efficiently without any upkeep, but this couldn’t be further from the truth. Over time, dust, dirt, and debris accumulate inside the system, particularly in the filters, coils, and vents. This buildup restricts airflow, forcing the system to work harder to cool your home, which in turn increases energy consumption.

Dirty filters alone can reduce airflow, making your system struggle to reach the desired temperature. When this happens, not only do you pay more in electricity costs, but your aircon is also at a higher risk of breakdowns, leading to expensive repairs or even premature system failure. The best way to prevent this issue is to schedule regular servicing at least once a year. A professional technician will clean and inspect your unit, ensuring that it’s operating at peak efficiency. Regular maintenance also allows small issues to be detected before they turn into costly repairs.

Setting the Temperature Too Low

Another common mistake is setting the controller too low, especially on hot summer days when the heat is unbearable. It might seem like cranking the aircon down to 16°C will cool your home faster, but in reality, all it does is make the system work harder, consuming excessive amounts of energy.

Many people don’t realise that an air conditioner cools at a constant rate, meaning setting it lower won’t make it cool faster; it simply extends the running time unnecessarily. Additionally, every degree lower than necessary can increase energy usage by around 10%, significantly impacting your electricity bill.

The optimal temperature setting for cooling is between 22°C and 24°C. This range ensures comfort while keeping energy consumption under control. Instead of setting the temperature to an extreme low, consider using fans to help circulate cool air more effectively. This way, you can create a comfortable indoor environment without overworking your air conditioning system. For more tips on staying cool this summer, check out our previous blog post here.

Leaving Doors and Windows Open While the Aircon is Running

Leaving doors and windows open while running your air conditioner is another major energy wasting mistake. When warm outdoor air enters your home while your air conditioner is operating, it forces the system to work overtime to maintain the desired temperature. This leads to longer running times and increased power consumption.

Even small gaps around windows and doors can allow cool air to escape and warm air to enter, which significantly reduces the efficiency of your system. The harder your air conditioner has to work, the higher your energy bill will be. This is particularly an issue for ducted air conditioning systems, where multiple rooms are being cooled at once, making it essential to ensure proper insulation.

To fix this, always ensure that all windows and doors are closed properly when using your air conditioner. Consider investing in weather stripping or draft stoppers to seal any gaps where air might be escaping. Additionally, using blockout curtains or blinds during the hottest parts of the day can help reduce heat gain from sunlight, allowing your air conditioning system to cool more efficiently.

Using the Wrong Fan Speed and Airflow Settings

Most modern air conditioners come with multiple fan speed settings, but many people don’t fully understand how to adjust them for maximum efficiency. Running your air conditioner on high fan speed constantly might seem like a good idea, but it can actually lead to uneven cooling, wasted energy, and excessive wear on the system.

If the fan speed is too high, it may cause the cool air to circulate too quickly, failing to remove excess humidity from the room effectively. On the other hand, running it on a very low setting might not distribute the air evenly, causing some areas to feel cooler while others remain warm.

One solution is to use auto mode whenever possible. This setting allows the air conditioner to adjust the fan speed based on the temperature needs of the room. If you need quick cooling, a high fan speed is fine, but once the temperature is stable, switching to medium or low speed helps maintain comfort while using less energy.

Not Using Zoning Correctly in Ducted Systems

For those with ducted air conditioning systems, improper use of zoning can significantly increase energy bills. Zoning allows you to cool only specific areas of your home rather than running the air conditioner throughout the entire house. However, many people mistakenly leave all zones active even when certain rooms are not in use. This results in unnecessary energy consumption, as the system works to cool areas that don’t need cooling.

A well-managed zoning system can cut down on energy use by up to 30%. If you’re home alone during the day, for example, there’s no need to cool empty bedrooms. Similarly, if everyone is in the living room in the evening, other areas of the house don’t need to be cooled at full capacity.

To make the most of your ducted system, only activate zones in occupied rooms and program schedules to ensure energy isn’t wasted. Some advanced zoning systems even come with smart controls and sensors that automatically adjust cooling based on room occupancy. If you’re unsure how to optimise your zoning, watch our video on how zoning works in a ducted air conditioner.

In Conclusion

By avoiding these five common air conditioning mistakes, you can significantly reduce your energy costs while improving your home’s cooling efficiency. Small changes like regular servicing, using the right controller settings, closing doors and windows, optimising fan speed, and managing zoning correctly can make a huge difference.

At Ford & Doonan Air Conditioning, we specialise in providing energy efficient air conditioning solutions, servicing, and expert advice to help you stay cool without unnecessary expenses. If you’d like to book a service, upgrade your system, or get personalised advice, reach out to us today.