How to achieve the official fuel economy figure

2012 has arrived and with it comes the usual swathe of resolutions covering everything from getting fit to going on that dream holiday.

However, our guess is the majority will involve saving money this year and with it comes a focus on most people’s largest outlay – the car.

From road tax to insurance to fuel costs, cars are not cheap to run. However, there are cars which can save a driver cash simply by offering lower CO2 emissions (and reduced road tax as a result) and greater fuel efficiency.

Even less ‘green’ cars have an official miles per gallon (mpg) figure given to the car when it is new. This should indicate the distance a car is capable of travelling on a gallon of fuel and how often a driver visits the pump.

However, as our 2011 guide suggests, that official fuel economy figure can be inaccurate in the real world, leading to some car owners even suing the company in the US.

As we explained in the guide, this is because the figure is taken from non-real world conditions and should only really be used as a comparison tool against other cars as opposed to a indicator of a car’s real world fuel economy.

Perhaps less drastic action would be to take measures to ensure you are getting as close to that figure as possible. The results could lead to hundreds of pounds a year in fuel being saved – perfect timing to pay for that gym membership!

Can I achieve the official mpg figure?

The simple answer is yes. The official figure is taken from a testing centre which doesn’t have traffic lights, road works and, more importantly, human drivers, but that does not mean it is impossible to achieve a figure.

For example, the annual RAC Future Car Challenge regularly sees drivers of low-CO2 cars such as the Seat Ibiza Ecomotive and Vauxhall Ampera extended-range electric car not just match, but exceed their official fuel consumption figure because of the expert eco-driving of the participants.

How to prepare your car for low-cost driving

You don’t need to rush out to buy a new car or even have aerodynamic packs fitted to your existing model to improve fuel economy and save yourself money – although it has to be said most new cars are significantly cheaper to own than older cars.

Instead, concentrate on the small things you can do to improve fuel economy in your car. The first step would be to shed some weight.

The less weight the engine has to power around the less fuel it will need. This means clearing out the boot of luggage and clutter (although the spare wheel will have to stay!) if it is not needed on the trip.

Roof bars and roof boxes should also be removed if they are not being used because not only are they adding unnecessary weight, they also make the car less aerodynamic.

Finally, check all four tyres are the correct pressure as listed in your owner’s manual. Apart from damaging the tyres themselves leading to more expense for replacements, under-inflated tyres will mean lower fuel economy and more trips to the pump.

What can I do while driving to improve fuel economy?

One of the first things you can do to improve fuel economy is to limit the use of air conditioning in the car. This may be more difficult in winter but the greater the difference between the temperature inside the car and the temperature outside the car, the more fuel a car will use for the air conditioning.

Things such as the radio also drain fuel but only be a small amount meaning it is probably safe to leave them on. However, heated rear windscreens and demisters will use fuel and should be turned off when they are not needed.

If you know where you are going it is less likely you will get lost and waste more fuel. Always plan journeys ahead through route planners – don’t just rely on satellite navigation – and check for traffic news to avoid busier areas wherever possible.

Driving tips for saving fuel

Once unnecessary luggage has been removed and tyre pressures have been checked it’s time to actually drive the car in a manner which will edge you closer to that official fuel consumption figure.

One obvious way of saving fuel is to not warm the engine up in winter. Not only does this waste fuel, it can also lead to cars being stolen while owners are clearing the windows. This practise is known as ‘frosting’ and is growing in regularity in the UK in recent years.

In the same vein, moving off as soon as the engine is switched on helps to save fuel. Once the car is moving, Renault suggests accelerating ‘briskly’ up to 30mph (where it is safe) and into fifth gear, but any acceleration over 30mph should be ‘restrained’.

Which brings us on to gear changes. Smoother gear changes will mean less fuel is used and driving in higher gears can also help.

Renault advises drivers to shift up to the next gear at approximately 2,000rpm in diesel and 2,400rpm in petrol cars and says in 30mph the car should already be in fourth or fifth gear.

Quickly accelerating and then decelerating can waste fuel and once up to speed it is advisable to keep a steady speed once at 30mph.

Anticipation is also key. By anticipating when the car needs to stop the driver can avoid excessive use of the brakes, allowing the car to slow naturally will save fuel.

When dealing with a hill you can take your foot off the accelerator in the downhill part to save fuel and keep to the same speed.

Unlike the tests for the official fuel consumption figure, chances are you will run into traffic. If this is the case, and the car is likely to remain idle for more than 30 seconds, it will probably save fuel if you turned the engine off.

Hitting the fuel economy figure

Careful eco driving coupled with shedding weight and planning a journey in advance are all important points when aiming for that official fuel economy figure and are all guaranteed to save you money on fuel.

However, it is just as important for all aspects of the car to be functioning to their optimum level to reach the official fuel economy figure.

This means all new and used cars should be serviced regularly to ensure they are in a good enough condition to save you money.

By taking your car in for a Perrys service, you are giving it the best possible chance of achieving optimum fuel economy.

To check if you are improving your fuel economy you can check the fuel economy display which is situated on the dashboard of some new cars.

For those without a digital readout fuel economy can be calculated by filling the tank and making a note of the mileage. Then divide the amount of fuel used by the number of miles covered.

Unfortunately, fuel pumps in the UK will give readouts in litres so you must convert litres to gallons before working out your car’s mpg.

This can be done by dividing the number of miles covered by the amount of litres and multiply the answer by 4.546 to get the final mpg figure.