Is it true that when you drive with your windows down, it saves your petrol? Regardless of whether it is scorching hot outside, there are some who tells you that if you drive with the windows down, which means that you are not utilizing the air-conditioning your car actually uses less petrol.
This is because it is found that the A/C actually use up a lot of power which means more fuel is burnt.
The answer is actually yes. Your car actually uses more power with the A/C on. However, there are situations when having the A/C on is better than using natural wind outside. So, depending on the speed you are travelling at, it would depend largely on the situation.
First things first, you have to be aware that driving with your windows down would actually involve more drag that will cut off the aerodynamics of the air flow. So when it requires more power to surge the car forward, you will then burn more fuel, which means you are back to square one.
So, to keep it simple, if you are in the city streets where your car is not free to move around much, keep the windows down and switch off the A/C. if you are on the highways, use the A/C and shut the windows because you are moving faster with less obstruction and you want to minimize drag. That way, you will surely save more petrol than usual.