A motoring expert has shared a scientific 'secret' that will help you save money on your fuel. 

Drivers across the UK have been grappling with high fuel prices for longer than they'd care to remember.

“Fuel prices have reached a five-month peak, exceeding 150p per litre, on average, across the UK," according to the team at Select Car Leasing.

Now that we're entering the better weather, motorists will also have to consider how to keep cool in their cars without spending a fortune on fuel along the way.

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As temperatures rise, drivers will have to decide to either turn on the air con or open the windows.

The leading vehicle lease company has shared their expertise to answer that very question and help your fuel go that much further.

Is it better to have the windows open or turn on the air conditioner in the car?

“Naturally, many of us assume rolling down the window instead of cranking up the aircon is a more fuel-efficient option," according to Select Car Leasing. 

“Science, however, may suggests otherwise, especially at higher speeds," the team continued.

To answer the question, the motoring experts explained how air conditioning systems work.

They derive their energy from the alternator, which is powered by the engine.

Cars are more aerodynamic when the windows are tightly shut. 

This means that air can freely flow over and around the car.

In contrast, when windows are open, air enters the main body of the vehicle which creates a ‘drag’.

The motoring experts explained: “This ‘drag’ forces your car’s engine to work harder than usual, resulting in the engine burning more fuel than it normally would if the windows were shut".  

The team also noted a study which was conducted by the Society of Automotive Engineers,

The research reported that at speeds greater than 45mph, fuel efficiency will decline more significantly if your windows are down, compared to the cost of using the car’s air conditioning.

For thus reason, the experts recommend that if you're travelling over 45mph you should shut the windows and opt for air conditioning instead to save yourself on fuel costs.

“Unfortunately, there is a potentially massive trade-off to be had here," the team warned.

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The pros continued: "While driving with open windows in slow bumper-to-bumper traffic below 45mph can save on fuel costs, it significantly compromises air quality inside the vehicle.

“Studies have shown that this practice can increase a driver's exposure to pollution by over 90 percent during peak traffic times.

“While the frustration of driving at a snail’s pace might cause a spike in your blood pressure, according to a recent study, so will exposure to pollution.