Do diesels offer better value for money?

For the first time ever in the UK, more new and used car buyers are choosing to go for diesel engines than petrol.

Figures published last week by the Society of Motor Manufacturers and Traders (SMMT) seem to indicate that increasingly, car buyers are looking at fuel efficiency rather than high performance. Last month sales of diesel cars accounted for 50.6% of the market, an occasion unprecedented in the UK since the engines were first introduced to Britain.

The news is likely to be welcomed by anyone selling a car with a diesel engine, who generally have suffered from the negative perception of the vehicles. However to a great extent, diesels poor reputation is undeserved - or at least, not anymore.

Whilst once they were widely criticised for slow acceleration and a trademark shudder when idling in traffic, advances in technology such as the 80's introduction of turbo-charged direct injection engines have made them as smooth a drive as the vast majority of petrol vehicles. 

The appeal of diesel engines lies in their reliability and more importantly, their fuel efficiency. On average diesel engines are 15-20% more efficient than petrol engines of the same size, with the current norm for diesel standing at 50 miles per gallon.

Since 2002 the engines have been popular among business users because under the emissions-based company car regime, their higher efficiency means a lower tax bill. Now though as private motorists look to tighten their belts following the recession - and as the premium prices for diesel cars has all but disappeared - many are turning to what the Guardian referred to as the "ugly duckling of motoring.''

One powerful motivation is the introduction of a "showroom tax" on the most polluting cars sold by dealerships this April. This can see both a higher initial and yearly tax disc attached to new petrol-engined models, which doesn't apply to diesel.

However though it seems like a straightforward saving, the cost of diesel fuel itself means that its actually a more complicated situation. In 2007 for example, diesel rose to 13p higher per litre than petrol. Today the difference is much lower - only 1.5p - but as the Guardian's Richard Wray elaborates, without the petrol-focused price competition between garages, diesel prices are often uncompetitive. Some garages even hike up the cost of diesel to support their cuts to petrol prices.

Then there's the question of repairs. Newer turbodiesels are complex systems and when they go wrong, the bill is often quite expensive. Without the comprehensive cover offered to company cars, private owners of some modern models may have to cover 80,000 miles or more to start to save money on fuel efficiency.

Whilst the calculations may be more complex than first seen, the figures are inarguable - there's never been a better time for a diesel owner looking to sell a car for cash.

 

Paul Revill, Nottingham, Toyota Yaris Verso

C.F. Millard, Bradford on Avon, Citroen C1