Money Mensch: How to drive down your petrol costs (literally)

By Martin Lewis, April 29, 2009
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The government’s 2p-a-litre hike in fuel duty means petrol prices are creeping near the pound-a-litre value again. Yet you can cut the annual cost of petrol and diesel by a third. It is all about combining three easy steps.

Find the cheapest petrol station
Savings of 3 to 5 per cent are possible by switching from the most expensive retailers to the cheapest. Using fuel to drive around and find the cheapest forecourt somewhat defeats the point, so the best way to do this is online.

Petrolprices.com will find the cheapest forecourt in your area. After registering, enter your postcode and tell it how far you are willing to travel. It lists the day’s cheapest petrol stations in that area for unleaded, diesel, LPG and other fuels.

There is also KeepMoving.co.uk, which shows the cheapest petrol stations along a given route, so if you are planning a journey, this is the site to use.

The differences in price may only be pennies per litre, but it can add up to £200 of savings in a year for regular drivers.

Increase car efficiency
Minor vehicle tweaks could knock 15 per cent off the cost of motoring, because most of us make our cars work too hard, using more petrol. For someone spending £50 a week on fuel, each percentage point saved cuts your cost by £25 a year.

● Keep your tyres correctly inflated. Lower tyre pressure increases the drag on a car, meaning you need more fuel. Checking the tyres regularly can increase your car’s efficiency by 3 per cent.

● Get rid of the junk in your trunk. The lighter your car, the less effort it takes it to accelerate.

● Take your roof rack off. Roof racks add massive wind resistance to a car, forcing it to work harder. Take off anything that makes your car less aerodynamic. Even closing windows will make a difference. All this can improve efficiency by 2 per cent.

● Turn off the air con. Air con is a massive drain on fuel; switch it off and you can make an 8 per cent energy saving.

● Do not fill up all the way. Fuel is heavy, so filling the tank to the brim adds quite a weight. Filling up slightly more often and putting less in — keeping the car half to three-quarters full — will make it run more efficiently. Then again, you may run out of fuel more quickly, necessitating an urgent trip.

The biggie: low-fuel driving
The savings here are massive. You can drive the same distance in the same time yet use considerably less fuel just by simply driving more smoothly. The RAC estimates some drivers can cut driving costs by up to 60 per cent, without losing time.

● Speed up smoothly. This will mean you take longer to reach your top speed, not that you will go slower. Try to keep the rev count under 3000.

● Use the highest gear possible without labouring the engine.

● Let the car slow gradually. Breaking is a waste of energy. If you know you are going to need to stop, then use your judgment and allow the car to slow down gradually.

● You need to be vigilant about your road position. Leave enough room to accelerate and move slowly. This can make a big difference.

An easy way to think about this is imagine the car in front accelerating hard away from a traffic light only to need to soon brake sharply at the next. If you are the car behind and slowly pull away and then slowly pull down, you are right behind yet you have used much less fuel.

When I first wrote about this on my website, I was met by quite a bit of scepticism. Yet soon feedback came of big differences; one driver had gone an extra 100 miles on a single tank of petrol.

I have even time tested these. When driving normally, I averaged 11.2 km per litre and 13.4 km per litre for efficient driving — an increase of 20 per cent. For someone who spends roughly £50 a week on fuel, that sort of saving adds up to £500 in a year.

Plus, the low-fuel driving did not make much difference to the journey length, only adding about 10 minutes in total. More info at www.moneysavingexpert.com/petrol

    Last updated: 4:55pm, April 29 2009