Should I buy a petrol, diesel or hybrid car?

petrol diesel or hybrid

In the past, deciding the fuel type of your new car was far simpler. Diesels were workhorses that sounded like black cabs, hybrids were the choice of the open-minded or open toe-sandaled, and petrol was for pure performance.

But those lines have become increasingly blurred. Most buyers can now opt for their preferred fuel, without compromising much on the car, or its performance out on the road. That said, you’re almost certainly better-suited to one fuel type over another, depending on your own driving habits, your budget and how eco-conscious you are, as our guide below explains in more detail.

Painting an honest picture of your own motoring mannerisms from the outset will really help narrow down your choices. Even in the hybrid category, there’s an engine set up to suit almost every occasion; with the battery pack taking on more or less of the responsibility for reducing fuel consumption and emissions. And while none have the range restrictions of a pure electric car, these inevitably suit some drivers better than others.

Suzuki Ignis SHVS badge

The Suzuki Ignis SHVS, for example, simply recovers, stores and recycles brake energy in the battery, and uses this to boost power and engine efficiency. All that technology enhances performance without increasing fuel consumption or emissions. Hybrids like the Toyota Prius use a similar system, but can also run in electric-only mode for a mile or two.

An increasingly popular line up of plug-in hybrid vehicles (commonly called PHEVs) such as the Mitsubishi Outlander PHEV, however, can be charged from a socket and will cover around 30 miles before the internal combustion engine kicks in. Finally, the recently deleted BMW i3 is essentially a full electric vehicle but uses a small motorcycle engine as an emergency back-up to get you home if the batteries die. This type of car is known as a range extender.

Which new car fuel should I buy?

With so many options, which fuel type should you choose? To help you make your mind up, here are a few key points worth bearing in mind before you buy.

Cost

the cost of fuel

Unless you’ve got a limitless budget, the cost of your car is going to be high up on your list of priorities. And that can vary enormously within one model range, depending on the type of fuel used to power it.

As a general rule of thumb, the more advanced or economical the car’s powertrain becomes, the more expensive the vehicle will be to buy. So a diesel-powered vehicle will cost more to buy than its petrol-engine equivalent, and the advanced technology behind a hybrid is likely to cost you more still. But the expense doesn’t end there, of course.

Fuel economy

While you’re weighing up list prices on the dealer forecourts, you also need to seriously consider how many miles you’re really going to travel each month. Fuel consumption can obviously vary enormously: with a diesel typically around 30 percent more economical to run than a petrol-engine vehicle, while a hybrid can be even more thrifty – with claims of up to 200mpg under official laboratory tests. But owners often find that these figures are radically different out on the road.

Volkswagen Golf GTE Advance

The fuel itself differs in price, too – with petrol currently costing almost 10p per litre less than diesel at the pumps. So you need to gauge your likely usage first. Better still, come up with an annual cost comparison, as we’ve done below with three derivatives of the Volkswagen Golf:

 VW Golf petrol: 1.4 TSI (5dr) DSG SE NavVW Golf diesel: 2.0 TDI (5dr) DSG SE NavVW Golf GTE hybrid: 1.4 TSI (5dr) DSG Advance
List price£22,865£25,515£32,600
Average fuel cost*120.6 per litre130.0 per litre120.6 per litre
Combined mpg54.3mpg64.2mpg156.9mpg
Annual fuel cost (10,000 miles)£1,009.68£920.55£349.43

* Based on average fuel prices (March 2019)

This illustrates that the diesel-powered Golf will only save you around £90 a year in fuel, assuming like-for-like driving styles over 10,000. Given that the car itself cost £2,650 more to buy, it’s going to take nearly 30 years, clocking up average mileage, to claw back that initial outlay.

By contrast, the Hybrid costs nearly £10,000 more than the petrol to buy, but it (theoretically) uses around one-third of the fuel. With around a £660 annual saving at the pumps, that it will take you just over 15 years to break even – less than half the time. That said, if you plug the car in to charge every day, use it for short commuting hops and only the occasional long journey, then you could easily exceed the claimed economy and you’ll recoup the extra outlay much sooner.

Of course, buyers aren’t only interested in saving money, when they opt for alternative fuelled cars, but these sums are worth calculating ahead of any new car purchase.

Driving habits

diesel filler cap

The type of miles you’re likely to be clocking up counts too. Are you going to be pottering around town, or steaming up and down the motorway all week? That’s relevant because some fuel types – namely diesel – are better-suited to driving long distances. That’s partly why they’re usually the fuel of choice of sales reps. Although the price per litre of fuel, and your initial outlay for the car itself, will be higher than a petrol-engine equivalent, if you’re putting enough miles on the clock, you should still be better off over a lease term.

A diesel will almost certainly deliver better fuel mileage and lower CO2 than a hybrid in such intensive driving circumstances – meaning diesel remains the eco-friendly choice for high-mileage motorists.

By contrast, if you only ever cover short distances each day, then you could find you have enough battery life between charges in a plug-in hybrid, and therefore rarely need to fill up all. More generally, petrol-fuelled cars are better in stop-start situations and are the best choice if you mainly drive in the city.

Longevity

plug-in hybrid charging

Technology is developing fast in the motor industry, in a bid to create safer and increasingly eco-friendly cars. But is this technology built to last? That’s of particular concern to buyers looking at electric-only or hybrid vehicles, which place huge reliance on the car’s battery power. How long will the cell last? And how much will it cost to replace?

Some manufacturers, such as Renault and Nissan, have introduced battery leasing schemes, to help alleviate those concerns. So if the cell fails, owners can automatically swap it for a new one. Other brands cover the hybrid and battery components under a separate warranty (typically five to eight years). Even so, buyers understandably feel like they’re stepping into unknown territory.

As for traditional fuel types, diesels have always been regarded as being more durable. But in fact, all modern engines should be capable of clocking up at least 200,000 miles, if serviced regularly. And in reality, it’s corrosion and the failure of high-cost parts that usually ends an old vehicle’s life.

Tax

CO2 emissions

Road tax has been dictated almost entirely by carbon dioxide (CO2) emissions since 2001. For all cars registered since then, the more your car pollutes the environment, the higher the tax you pay; with electric cars and hybrids enjoying a zero-rate. So for motorists on a budget, it’s made sense to bear that extra duty in mind, if they’re opting for a fuel type that’s heavily taxed.

But the current Vehicle Excise Duty rules have reduced the impact of emissions on road tax. These state that cars registered from April 2017 will only be taxed based on their CO2 emissions for their first 12 months – which is always included in the dealer’s ‘on the road’ list price anyway. Thereafter, owners will pay a flat rate of £140 per year. Only zero emissions, electric-only cars will remain tax-free. While alternative fuel vehicles – namely, hybrids – incur a slightly cheaper fee, at £130.

The environment

The most recent, advanced technology is almost certainly going to be the eco-friendliest. But the Government’s ever-changing stance on what’s bad for the environment, and the levies that accompany that, make the decision over what to buy increasingly difficult for motorists. Also, even plug-in hybrids and pure electric vehicles aren’t totally in the clear, as the electricity used to charge their batteries usually comes from polluting power stations.

JATO CO2 emissions

Petrol power has for a long time been considered the bad boy of the fuel pumps; slammed for its high levels of carbon emissions. So businesses were once actually incentivised to stock their fleets with diesels. However, diesel cars have been stripped of their eco-credentials recently, and governments and local authorities are considering ways to cut the use of diesels in urban areas.

Carmakers are at pains, however, to stress that the latest Euro 6 diesels are virtually as clean as petrol cars in all measurable tailpipe emissions. Older diesels pollute more, but new diesels do not – so you can buy a brand new diesel safe in the knowledge its exhaust emissions are ultra-clean.

Admittedly, changing current public perceptions to stress that showroom-fresh new diesels are not ‘bad’ may take some time in the current climate…