But what's the real truth? Are diesel cars bad? And is it worth buying a diesel car? Let's take a look at the facts about diesel cars, what they're good at and under what circumstances it makes sense to go diesel.
Should I buy a diesel car?
You should consider buying a diesel car if you're making regular motorway journeys or if you plan on towing a caravan or trailer on a semi-regular basis.
Generally speaking, diesels can achieve much better fuel economy than a comparable petrol car on long journeys when travelling at speeds between 50-70mph for the majority of the trip. Journeys will likely be cheaper to make in a diesel car, despite its higher per-litre price at the pump.
Diesel cars make excellent towing vehicles because they have lots of torque, which is a technical term for pulling power. They can often tow more than equivalent petrol cars, making light work of even the heaviest loads.
What is the future of diesel cars?
In the short to medium term, there's nothing on the horizon that should worry you when considering buying a diesel car. The government plans on introducing a ban on the sale of petrol and diesel cars in 2035, but this only affects brand new cars.
Unless major changes are announced, diesel cars - and vans - will still be on our roads for many years yet and you will still be able to buy a used diesel car even after the ban has been introduced.
With this in mind, buying a diesel car at the current time will not cause you any additional inconveniences or headaches.
What about diesel emissions?
There are two primary substances that vehicles emit that the government wants to measure and control: Carbon Dioxide (CO2) and Nitrous Oxide NOx.
Typically, a diesel car emits 15-20% less CO2 than a petrol car with like-for-like performance, according to the Society for Motor Manufacturers and Traders. This is not true of petrol/electric hybrid cars, which emit substantially less CO2 than conventional petrol or diesel cars.
The big question about diesels has been NOx and their impact on air quality, particularly in towns and cities where populations are dense. The truth is that the latest diesel cars are the cleanest the world has ever seen, emitting 84% less NOx than cars built just two decades ago thanks to high-tech filtration exhaust systems.
It is really only older diesel cars that significantly contribute to a reduction in air quality. Tests by Which? revealed that some diesel cars actually emit less NOx than equivalent petrol variants.
Most economical diesel cars
The most economical diesel car on sale right now in the UK is the Vauxhall Corsa, which is capable of achieving a remarkable 88 mpg thanks to its ultra-efficient 1.5-litre turbocharged diesel engine. This is closely followed by the Ford Focus and DS 3 Crossback, which achieve 80 and 76 mpg respectively and again use 1.5-litre engines.
Other new diesel cars that can achieve over 70 mpg include:
- Vauxhall Crossland X
- Peugeot 308 and 508
- Nissan Qashqai
- SEAT Ibiza
- Mercedes-Benz A-Class
- BMW 1 Series
- Dacia Logan MCV
- Kia Ceed
Is it worth buying a diesel?
It depends on your circumstances and what you are going to be using the car for. Diesel cars can definitely be worth buying if you:
- Travel more than 10,000 miles per year
- Need to tow a caravan or trailer
- Regularly use the motorway
- Mostly do long journeys
If you commute into towns or cities, such as London that have an ultra-low emission zone, you should check the vehicle meets Euro 6 standards. Most modern diesel cars do, but it's better to check before you buy.
The facts about diesel cars
In summary, the truth about diesel cars is that:
- Modern diesels are just as clean as equivalent petrol engines in terms of NOx emissions
- Diesels generally produce lower amounts of CO2
- Diesels achieve excellent fuel economy at motorway speeds
- It can absolutely be worth buying a diesel car depending on what you use the car for
- New diesel cars will be on sale until at least 2035 (unless new laws are introduced)