Fuel Efficiency: Filter fact from fiction

Published by Nathalie Bonney on 14 May 2010.
Last updated on 03 May 2011

fuel hose

From Friday 1 October, when the government's fuel duty rise kicks in, UK motorists will need to fork out another penny for each litre of petrol or diesel they buy.

And while fuel prices may have edged down after hitting record highs in the spring, an increase in wholesale prices soon threatens to put that trend in reverse, according to September's fuel price report from the AA.

The long and short of it is, coupled with today's touch economic climate and looming austerity measures, drivers have never been more motivated to find ways to be more fuel-efficient when you're driving.

But can you separate the fact from the fiction when it comes to taking fuel-efficiency measures?

Keep your car in good condition: Fact

Get your car serviced regularly to ensure the engine is efficient. Use the recommended oil and petrol for your vehicle – refer to the handbook if you don't know what type to use.

You can also improve your fuel economy by 5%, provided you keep your tyres inflated to the correct pressure. Again, the handbook should tell you what this is.

Drive with less weight in the car: Fact

The heavier your carload the more fuel will be needed to move your vehicle along. Don't leave stuff in the boot you rarely use.

In the same way, leaving roof racks or boxes on the top of your car when you don't need them creates extra wind resistance and again means your car has to use more fuel to combat this.

Turn the aircon off: Fact

Air conditioning uses up more energy, so use it sparingly. The same applies for other electrical features such as heated rear windscreens and demisters – only use them if absolutely necessary.

Open the window: Fact & Myth

Opening windows is an easy way to solve the aircon problem – but only if driving at lower speeds. For higher speeds, revert back to aircon as open windows create an air drag, which causes your car to burn more fuel.

Coast down hills: Myth

This was a common belief in the past; however, it's unsafe to do this because you are out of gear and not in control of your vehicle. 


Not only are you unable to accelerate away from a potentially dangerous situation, but you lose engine-braking, which takes some of the strain off the brakes on inclines.

In fact, most vehicle fuel systems will now have an ECU (electronic control unit). This means when you take your foot off the accelerator, the fuel supply will be cut to the interjectors.

Modern diesel engines can even shut off fuel when you remove your foot from the accelerator.

Fill up your tank at night or in the morning: Myth

The premise behind this idea is that, at the coolest times of day, you get more petrol for your pounds because fluid is denser in cooler temperatures. However, consumer tests show that the difference is minimal.

Drive more slowly: Myth

It's true that driving fast eats up your fuel, and for every five miles that you drive over 60mph, you reduce your fuel economy by 10%. However, driving in the incorrect gear isn't fuel-efficient: the lower gears use up more petrol.

Driving sensibly and smoothly is the most fuel-efficient way to drive, so don't slam your foot on the brakes or unnecessarily rev your engine.

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