Your driving habits
The types of roads you drive on will impact on your choice between diesel and petrol
Choosing between petrol and diesel has a lot do with your driving habits; including how often you drive, how far you go and what sort of roads you use. It’s not just about the cost of the fuel, either. Repair bills will also be dependent on how much you use the vehicle. Here’s our quick guide to matching the type fuel to your personal requirements.
Annual mileage: If you’re considering a new car, then the number of miles you drive is an extremely important part of deciding between petrol and diesel. This relates to how long it will take the diesel’s superior fuel efficiency to offset its increased purchase price and higher price-per-litre cost. The exact amount of miles you will need to drive depends on the car you buy, but with 2013 Department for Transport figures stating the annual mileage for UK drivers was just 7,900, most would not benefit from owning a diesel. For example, a Ford Focus owner driving 8,000 miles would take three years to make money with a diesel version. However, a driver covering 12,000 miles a year would cover the initial diesel premium on the Focus by year two. The more expensive the car – the longer it’s likely take to recoup your cash.
Find out how many miles you’d need to drive to make diesel pay: Use this Which? tool to calculate how long it will take to cover the additional diesel premium you’ll be charged.
Driving time: Do you use your car for commuting, or other regular journeys? This will be another deciding factor between petrol and diesel models. If your journeys take less than 15 minutes to complete, then both types of engines will be pretty useless and negate cost-saving benefits of either fuel. As a rule, longer journeys will tend to suit diesel cars, but this will also rely on journey type. See our next point.
Type of road: If you’re winding your way through clogged city arteries with endless stop-start motoring, then diesel cars would traditionally be ‘less wasteful’ than petrols. However, new-style city cars with small, three-cylinder engines and diesel-shaming mpg figures are rapidly taking over. Add to this their low-CO2 emissions and equally low road-tax charges and it’s easy to see why many choose petrol over diesel for urban driving. However, if the majority of your motoring is on motorways and A-roads, then diesel is only option you should consider.
Congestion charge confusion: Another question mark over the wisdom of diesels for city drivers has been thrown into the mix by Boris Johnson suggesting owners are hit with a £10.00 surcharge on the London Congestion Charge. If brought in, it’s likely this would be replicated across many UK cities – effectively sounding the death knell for metropolitan oil burners.
Service costs and driving: Modern diesel cars must be fitted with a diesel particulate filter (DPF) to cut pollutants. While this will please EU bureaucrats, the new ruling has also cost diesel-car owners thousands in repair costs. Using a diesel for short journeys will result in the filter getting clogged and causing serious damage if not cleared. Most cars try to do this automatically, but if your journeys are too short, the process will be ineffective. If this happens, the warning light will come on. It is possible clear the warning light by driving for 10 minutes or so at speeds greater than 40mph. However, if this is not continuous the process will fail. If diesel drivers continue to ignore the warning light, the car’s performance will deteriorate and the likely result will be a trip to the garage for a new DPF – costing at least £1000. Just another reason why the type of journey you take should form a large part of your decision-making process.