Air conditioning vs open windows

Everyone wants to keep cool while driving in hot roads this spring, but which is more efficient - cracking open the windows or turning the air conditioner on?

Turning the AC up is not great for fuel consumption, no matter what speed you are going, but rolling the windows down creates drag, which means the car uses more fuel. It may seem like a lose-lose situation but the benefits of staying cool far outweigh the negatives.

Overheating increases the risk of dehydration and sunstroke so it is definitely worth the extra pennies to keep employees healthy. However, the question of which cooling method to use still remains.

Research in the area suggests that speed is a factor worth considering, as the aerodynamics of your fleet may be reduced when the windows are opened.

It is best to keep windows down and the air conditioning off when driving short distances in town as slower speeds shouldn't affect aerodynamics too much.

For those driving on motorways or going at speeds upwards of 70 km it is more fuel efficient to turn the air conditioning on as wind drag can reduce fuel efficiency by 10 per cent.

If you drive at a speed over 88 km/h with the windows down fuel economy decreases by at least 20 per cent.

Tips to keep cool behind the wheel

-  Park cars in the shade or invest in windscreen shades so they are not too hot when drivers jump behind the wheel.

- When the whole car won't fit under the shade, put the front under and leave the back in the sun so the steering wheel and front seats don't get too hot.

-  If you look after fleet services, encourage drivers to carry bottled water with them so they don't get dehydrated.

- Have an emergency kit in the car, with extra water, just in case.

- Urge drivers to be careful with leather seats and metal belt buckles as these can quickly heat up in the sun.



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