Even as we enter the electric era, the age-old debate between petrol and diesel cars continues to rage on.
So: which one is better for you, and why?
Let's find out.
Car Cost
A diesel car is usually more expensive than an equivalent petrol model in almost every case, though not by a great deal.
Needless to say, you won't have that initial buying problem with leasing, as you're paying in monthly instalments, often with the choice of paying no deposit.
Fuel Costs
Don't be misled by the fact that because petrol is a few pence per litre cheaper than diesel at the pump. That may be the case on the face of it, but diesel engines are actually more efficient than their petrol counterparts and have better fuel economy, which means that a diesel will almost always be cheaper to keep filled up.
For example, if a litre of petrol costs £1.70 and a litre of diesel fuel costs £1.82, then a petrol driver will pay £102 to fill up a 60-litre tank, whilst a diesel motorist will pay £109.20. But the petrol driver will only manage to cover 582 miles on that full tank, whereas the diesel driver will manage 749 miles.
So if we assume those figures, and apply them over the course of three years (assuming you've done 20,000 miles in that time), then the diesel driver will have saved £1,740 compared to the petrol driver.
Yikes.
The actual cost of diesel cars themselves is widely accepted to be more expensive, with manufacturers asking more for diesel models than their petrol counterparts. But if you drive a tonne of miles each year, the better fuel efficiency of diesel cars will offset that cost, giving you better value for money.
Emissions and the Environment
Diesel fuel does contain slightly more carbon (2.68kg CO₂/litre) than petrol (fuel 2.31kg CO₂/litre), but the overall CO₂ emissions that diesel cars emit actually tend to be lower.
Of course, neither petrol nor diesel can be said to be good for the planet, so it's really just 'less worse'. But whilst diesel produces less CO₂, they also produce lots of other pollutants such as nitrous oxides (NOx), soot particulates and hydrocarbons which are linked to asthma along with other breathing conditions.
So neither are exactly helping the planet, but diesels are a little better.
Petrol vs Diesel: Driving Style
There are some differences between how petrol and diesel cars drive.
For starters, diesel cars have more torque, leading to greater pulling power, and you'll find overtaking on the motorway to be a lot easier. That makes diesel cars ideal if you own a trailer or a caravan and need to tow on a regular basis.
Overtaking in a petrol car is a bit harder. You need more gear changes and gas, although there are petrol engines entering the market which aim to rectify this disadvantage. Examples include Ford's 1.0-litre 'EcoBoost' engine and Nissan's 1.3-litre 'DIG-T'.
One criticism often levelled at diesel cars is their noise factor. However, whilst older diesel cars generally used to be very loud, that's less so today. Some might also rattle or clatter when idling and when revved, but it's not something so major that it's going to affect your entire driving experience. You'll also be glad to know that nearly all diesel cars in the UK today feature turbocharging, which helps smooth our the engine noise.
When a Diesel Car Might be Better
A car with a diesel engine is best if you find yourself putting in a lot of miles on a regular basis. So if a smooth, comfortable ride in which you don't have to think about much is your regular go-to, then a diesel is the way to go. you want a smooth and comfortable drive which you don’t have to think too much about, a diesel car might be best for you.
A diesel might not be ideal if you live in a major city with lots of stopping points and traffic lights, or if you drive a lot of small journeys.
When a Petrol Car Might be Better
A petrol car would be ideal for multiple short trips if you live in a major city or urban area and don't need to make a lot of long journeys, particularly if you only have the car for the short-term.
Diesel Particulate Filter
Most diesel cars are fitted with diesel particulate filters, and what they do is capture and store exhaust soot in order to reduce emissions. But because they only have a finite capacity, the trapped soot has to regularly be emptied or 'burned off' for the system to regenerate.
This can be done by high speed driving on motorways every so often, which is great, because diesels work wonders with motorway driving.
Don't worry. You won't have to drive at high speed every day (once a week should do it), but if you don't let the particulate filter burn off at all, then it can lead to mechanical problems later on. Luckily, most diesel cars are fitted with a filter warning light, which urges you to get onto a motorway pronto and burn off that soot.
Insurance
As for insurance costs, a car's market value and engine size will generally have a larger impact on what you pay than the type of fuel the car uses uses.
So seeing as diesel cars often come with a slightly higher chance of suffering repairs and replacements, that will translate to higher insurance costs, but not by much.
Servicing
Again, because diesel cars usually have more intricate internal systems than their petrol counterparts, this can lead to more servicing costs. And it's also worth mentioning that older diesel models usually tend to have worse MOT pass rates than petrol equivalents.
Tax
Considering that tax prices are determined on a scaling basis, the tax on a diesel car, being more fuel efficient, generally costs a little less than the tax on a petrol car.
The exact amount of road tax you will be paying for a petrol and diesel car depends on the date when it was first registered. The car is going to maintain the initial tax rate even in the event of a resale.
The UK's existing tax systems in the UK are as follows:
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Before April 2017: Official CO2 emissions are used to determine the tax rates for this bracket. Cars producing no more than 100g/km of CO2 are exempt from car tax. Hybrid and diesel cars registered in this period experience low tax rates or are tax-free because of their lower carbon emissions.
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After April 1, 2017: Cars registered during this timeframe only made the first payment based on CO2 emissions. After this point, they are subjected to a fixed rate tax equalling £155 per year (or £145 for hybrid vehicles). Zero-emission cars are the only vehicles exempt from car tax in this scheme.
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After April 1, 2018: A diesel car will be subjected to a higher tax rate during the first year, unless it meets the Euro 6d standard.
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After January 1, 2021: Euro 6d became compulsory for all new cars sold in the UK, meaning that owners of diesel cars registered after this date don't pay higher tax during their first year of ownership.
So as you can see, if you own an older diesel vehicle, you may end up paying higher car tax.
Will Diesel Cars be Banned?
The sale of new ones certainly will.
Yep, and that's because the UK government plans to fully transition to zero emissions vans and cars by the year 2035. So from 2035, the government is banning the sale of all new diesel and petrol cars completely (though 2030 was original date). The proposed changes are still a few years away, but the future of diesel cars doesn't look promising at all.
However, although the timeline for banning the sales of petrol and diesel cars is set in stone, there are no official plans to outlaw the use or resale of used, second-hand diesel cars. But the government's plan to minimise harm to the environment implies that local councils will take actions such as:
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Encouraging people to drive electric vehicles
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Changing road layouts at points of congestion
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Investing in low-emission buses and stimulating the use of public transport
And if these measures don't prove to be successful, authorities can still introduce local restrictions.
So yes, even if ALL diesel cars won't get outright banned, the odds do seem stacked against them.
Electric Cars
Of course, with electric cars you can bypass a lot of the shortcomings that come with petrols and diesels. There's no noise, no smell of gas, and no visiting fuel stations every other week.
However, it's not all Heaven, as electric cars also come with their own concerns. You'll have to charge them up at public places, for one thing, as you might not have access to a home charger.
Are Electric and Hybrid Cars the Future?
Pretty much, although that's not to say there won't be ANY room left for petrol and diesel cars in the modern world.
According to the Society of Motor Manufacturers and Traders (SMMT), there was a 60% drop in diesel vehicle registrations in the year 2020, and the same year also saw a 47.5% decrease in petrol vehicle registrations as well as a 161% increase in battery-electric vehicle sales.
And as part of the government's ten-point plan for a green industrial revolution which was released at the end of 2020, it took on the initiative of equipping England's major A roads and motorways with approximately 6,000 high-powered charging points.
The UK government is also aiming to:
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Introduce a new low-emission regulatory regime in 2024.
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Place zero-emission cars in a favourable position with car tax rates until at least March 2025.
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Invest £582 million for plug-in grants in order to reduce prices for zero-emission vehicle stickers until at least 2022/23.
In conclusion, it's safe to say that electrics and hybrids will be getting even more of an uplift than they are now.
Summary
So then, which is better?
Well, we feel safe in saying that there's not really a correct answer here.
Diesel certainly has a lot in its favour, but whether you go for a diesel or petrol car largely depends on your vehicle requirements and whether you want power or efficiency, or short or long-distance regular travel.
In the end, the choice is yours.