- Aug 2015

Does the aircon really waste fuel?

Technology Tuesday: Does the aircon really waste fuel?

Being young comes with many positives, you have energy, optimism and your whole life ahead of you. What many young people don’t have is money and as we know, money makes things happen. Money gets you those nice clothes, pays for your nights out and puts an important liquid into your car. That important liquid called petrol is one of the most important factors in a young persons life. It often is the deciding factor regarding where you’re going to go out that night or even if you’re going to go out that night.

I’m sure you have been in a car with your friends during the burning summer, windows rolled down but the breeze still feels like a sauna. You suggest that the driver switches the aircon on but he or she replies, “My dad said the aircon wastes petrol so I can’t switch it on”. At this point it’s so hot you’re willing to sacrifice your food money, to pay for the supposed fuel that will be wasted because the aircon is on. The real question is, does the aircon really waste fuel? Or is it just an urban legend told by the older generation to troll us? Well here’s a little run down as to how the aircon works.

The aircon is powered by the a device called the alternator, this device uses power from the engine to charge the battery of the car. The aircon has a compressor which also uses power from the alternator. Since all the components use engine power, when they’re working they put added stress to the engine of the car, forcing it work harder and use more fuel. So yes, having the aircon on does indeed use more fuel when driving. So what is the alternative? Simply rolling the windows down? Not entirely.

Rolling the windows down causes more drag on the car (wind travelling against the car at speed) and this also wastes more fuel. The amount of drag on your car depends what on speeds you are travelling, so if you’re on the highway there will be more drag if your windows are open and your car will use more fuel. There will be dramatically less drag on your car if you are travelling in the city at lower speeds and the effect on your fuel consumption will be decreased. Smart people have researched this topic extensively and have come up with the following conclusion. When you’re driving on the highway, it is more fuel efficient to travel with your windows up and the aircon on because the drag on your car wastes more fuel than having the aircon on. Whereas when you’re in the city travelling at lower speeds, it is better to have you’re aircon off and your windows down because the drag is far less when you’re driving slower.

So when you’re cruising on the streets with your mates, you’re going to have to bear with the hot winds in the summer if you plan on saving more fuel. The good thing is that when you go for road trips or long distances, you can confidently put the aircon on and know that you’re not wasting petrol. Happy Tech Tuesday Motorists.

Image courtesy of www.ncae.com.au