This is something that you might have debated with your friends for a long time especially on long car trips.

The question on which consumes more fuel whether cooling the car with the windows down or running the air conditioner with the windows up has been an age long argument. In this article, we’ll learn about the difference between the two and which one would be more efficient given the circumstance.

Aircon On or Windows Down?

A study conducted by the Society of Automotive Engineers (SAE) found that driving with the air conditioning system on with the windows up is often a more fuel-efficient approach when driving.


This study was made at wind tunnel and a desert track owned by General Motors. In the wind tunnel scenario, the air was forced at the front of the vehicle and from an angle on the car’s front as a means to simulate crosswind. Meanwhile, in the desert, the vehicle speed and temperatures were accounted for in the study. There were two vehicles used in the test, the first being a full-size SUV with an 8.1-liter V-8 engine and the second was a sedan that is equipped with a 4.6-liter V-8 engine.

The overall results showed in these two studies that there was a major negative effect when driving with the windows down on the fuel efficiency of both vehicles. It was higher than using the air conditioning system.

The sedan with its windows down had lost efficiency by around 20% while the fuel efficiency of the SUV was reduced to just 8%. Such differences are crucial factors in figuring out just how much the windows down choice can affect the efficiency of fuel consumption. This study also concluded that the more aerodynamic a vehicle is, the higher the drag when the windows are open.

Using Aircon in Winter

The answer if you should run the air conditioning system of your car even in winter is yes. It is important to do so even just for 10 minutes every two weeks in order to let the coolant circulate throughout its system. The reason for this is because there is a lubricant in the coolant that aids in keeping the pipework and rubber seals of the system in good condition. If you fail to use the air conditioning system for a long time, your AC can stop working because there isn’t any coolant and lubricant to work on the rubber parts.

This can lead to seals that are leaky and can cause your coolant to evaporate, which results in an inefficient AC system for your car when you need it. Furthermore, moisture can also build up in its air vent ducts if it isn’t used frequently which could lead to the formation of bacteria and mould. This can be harmful to you and your passengers when you start the system after months of inactivity.

Aside from that, air conditioning in your car is also important when you’re having a hard time with visibility during the winter months. The reason for this is because it also dries the air in the vehicle besides keeping it cool.

If you’re looking for an automotive expert who can help with the repair and maintenance of your vehicle, contact us at Peter Wilkinson & Co now!


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