Petrol vs diesel cars

When it comes to buying a new car, there’s a lot to think about – such as whether it should be diesel or petrol. Diesel is getting a bad rap, so is it time to ditch it, or are there a few more miles left in the tank?

Julie Daniels

Insurance expert

minute read

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Should I get a diesel or petrol car?

When you’re comparing the merits of diesel and petrol, there are a number of factors to think about:

Are diesel or petrol cars cheaper to run?

Diesel cars tend to be more expensive to buy than petrol cars, and diesel fuel is slightly more expensive. But if you use the motorway a lot and travel more than 12,000 miles a year, the diesel car has better fuel consumption and so is likely to be more economical.

However, it’s worth bearing in mind that the average UK driver now travels less than 9,000 miles a year, so you may well find it’s not worth the extra outlay.

Are diesel or petrol cars better for the environment?

Diesel cars were initially welcomed for reducing carbon emissions. But they were found to produce higher levels of particulates – tiny bits of soot that enter the lungs and lead to asthma attacks.

Some 10,000 Londoners a year are dying because of air pollution, and diesel cars are thought to be a big part of the problem. Because of that, parts of London are already banning diesel cars, and other cities look likely to follow suit.

Will I pay more in tax for a diesel or petrol car?

Tax rates for diesel cars have changed. It used to be that diesel cars enjoyed low tax rates, thanks to their low CO2 emissions.

But now they’re known to be a big cause of pollution, they’ve been hit with higher tax rates. On a diesel car, you’ll pay £140 per year after the second year of ownership. That tax hike, along with the extra money you’re paying both for fuel and the car itself, could make diesel cars a pricey option, even taking their fuel economy into account.

Diesel cars are set to be hit with bigger taxes from 2020, and from 2040 new petrol and diesel cars will be banned from sale altogether. So, you might find that, even now, it’s better to go for a cleaner option, like an electric or hybrid car.

Will having a diesel or petrol car affect my car insurance?

That’s not so clear cut. The cost of your premium depends on a number of factors, not just what type of car you have. When they’re totting up your bill, insurance providers will take into account:

your age
where you live
how long you’ve been driving
how many miles you drive each year
whether you’ve got any driving convictions
whether you have a no-claims bonus (and if so, how many years’ worth)

When it comes to assessing your car, there’s also other factors that impact your car insurance, such as its age, value, security, and any modifications. Your insurance provider will also consider the cost of repair and replacement parts. Many newer diesel cars have fancy filters and emission-busting systems, which can make them costlier to repair than their petrol counterparts. This could lead to higher insurance premiums.