There’s never been so much choice in the new car market, and not only do consumers have to decide between all the various different models, but they also have to decide between petrol, diesel, hybrid, plug-in hybrid and fully electric vehicles: not easy when you’re looking for the most eco-friendly choice. The automotive landscape can seem a bewildering place at the best of times, and trying to work out which option is best can be a challenge.
While petrol and diesel cars now have lots of competition from electrified vehicles, they can still be a good choice for many buyers. There are plug-in hybrid options, too, but these models tend to only offer short electric-only ranges, and tend not to be the most fuel-efficient cars in the real world, so fully electric or diesel-only cars can actually prove to be a greener choice.
For those after the greenest car of any given type, we’ve compiled this list of the brand new cars that give you the most return on the fuel you put in it, whatever form that fuel may take. For each fuel type, we’ve listed the top three most efficient cars available in descending order.
For cars that use fossil fuel (so petrol, diesel, self-charging hybrids and plug-in hybrids), that means the cars with the best miles-per-gallon (mpg) figures according to official WLTP testing.
The electric-car equivalent of this is known as the miles-per-kilowatt-hour figure, which is the amount of miles you can travel for each kWh of electricity you put in. There’s another snag, though, because although WLTP tests do produce these figures, they’re often not published by manufacturers: that’s because it’s thought that people care more about things like range and battery capacity, rather than efficiency. So, for these figures, we’ve taken efficiency data published by independent website evdatabase.org, and filtered the numbers by efficiency to bring you what that website believes to be the three most efficient electric cars on sale today.
So, read on to discover the best green cars that the new car market has to offer.
The Best Green Cars 2024:
- The Best Green Petrol Cars
- The Best Green Diesel Cars
- The Best Green Self-Charging Hybrid Cars
- The Best Green Plug-in Hybrid Cars
- The Best Green Electric Cars
The Best Green Petrol Cars
1. Mazda 2 1.5 90 Skyactiv-G
WLTP Fuel Consumption: 60.1mpg
Having been around since 2015, the Mazda 2 is getting very long-in-the-tooth these days, but despite its age, it still manages to deliver good enough efficiency to lead this list, making it the most efficient new petrol car money can buy. Indeed, in 1.5 90 Skyactiv-G form, the little Mazda is the only pure-petrol car remaining on sale that’ll crack the 60mpg mark. There’s much more to like than just its fuel economy, too. It looks smart and sophisticated, both on the outside and the inside, and even the entry-level versions come well equipped, most notably with a brilliant infotainment system that’s a doddle to use. Sure, the powertrain isn’t as impressive for performance or refinement as it is for efficiency, and the car’s driving manners can be a little rough and ready at times. However, if ultimate economy from a traditionally powered petrol car is your priority, then there’s literally nothing to beat it.
Mazda 2 Review
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2. Citroen C3 PureTech 110 EAT6
WLTP fuel consumption: 59.8mpg
Next up on our list of the most efficient petrol-powered cars is the Citroen C3. As is traditional with the French brand, the C3 is a quirky little car that goes about things its own way, with funky looks inside and out, and heaps of character. It’s also very strong on affordability, which complements the low running costs you get from its 1.2-litre Puretech petrol engine. This three-cylinder turbocharged unit is the same one found in countless other models produced and sold by parent company Stellantis (such as the Peugeot 208 and Vauxhall Corsa, to name but two), but the C3 is pretty much the only model that still offers it in 110 horsepower guise, paired with the six-speed automatic gearbox. This is a combination that allows a super-impressive fuel return of 59.8mpg according to WLTP tests.
Citroen C3 Review
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3. Suzuki Swift 1.2 Dualjet MHEV
WLTP Fuel Consumption: 59.7mpg
The Suzuki Swift is a characterful little supermini from Japan. The 1.2-litre petrol engine is fitted with mild hybrid technology, allowing an impressive fuel return of 59.7mpg. “Mild hybrid?!”, we hear you cry. “Doesn’t that mean it should be considered further down in the hybrids section?” Well no, because despite what Suzuki’s marketing department would like you to believe, it’s not a proper hybrid: the componentry fitted amounts to little more than a clever starter motor that provides a tiny bit of extra shove when pulling away to take some of the burden off the petrol engine. However, that small amount of help is enough to make the Swift one of the most efficient petrol cars you can buy brand new. It’s a very likeable car in a variety of other ways, too: it looks good, it has decent practicality, it’s affordable, it’s well equipped and it’s fun to drive.
Suzuki Swift Review
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The Best Green Diesel Cars
1. Volkswagen Golf 2.0 TDI 115 Life
WLTP Fuel Consumption: 67.5mpg
It seems slightly ironic that the most efficient diesel car on our list - and thus, the most efficient diesel car currently on sale in the UK - is made by the very company that could be accused of starting the whole backlash against diesel in the first place. The world does indeed work in mysterious ways. This version of the all-conquering Volkswagen Golf is packing the same 114bhp diesel engine as its Skoda-badged stablemate below (despite the slightly misleading naming), but the Golf’s more diminutive proportions and lower weight mean that it’s marginally more economical. That makes it an even better proposition for those who regularly do interstellar motorway mileages. So does the strong refinement and cosseting ride comfort, which help deliver you to your destination fresh and unfrazzled. Despite the impressive comfort, you also get sharp, alert handling, while the smart interior is packed with tech, including a pair of digital screens and various connected functions.
Volkswagen Golf Review
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2. Skoda Octavia 2.0 TDI 116 SE Technology
WLTP Fuel Consumption: 67.3mpg
The Skoda Octavia has always been a car that’s suited a diesel engine, so it’s good news that you can still have it with one, and it’s even better news that the Octavia is one of the most efficient diesel-powered new cars you can buy. The 2.0-litre diesel engine beneath the Skoda’s bonnet only has a fairly modest 114bhp, but that helps towards a super-impressive WLTP fuel economy figure of 67.3mpg. And why does a diesel engine feel like such a good fit for the Octavia? Well, because it delivers a generally relaxed and easy-going driving experience, which suits the lazy-yet-muscular power delivery of a diesel, and when you fill up the peerlessly spacious cabin with people and luggage, a diesel engine has the pulling power to cope with all that weight. The Octavia also provides a smart and solidly built cabin, and the fact that the car is also well equipped and affordable to buy merely tops off the package.
Skoda Octavia Review
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3. Citroen C3 Aircross BlueHDi 110 Max 6MT
WLTP Fuel Consumption: 64.0mpg
Diesel engines have already been largely purged from most model ranges within the sprawling Stellantis group, but the Citroen C3 Aircross range is one of the few where diesel is still on offer. You have to select top-of-the-range Max trim to get access to the 108bhp 1.5-litre diesel engine, so it’s not the cheapest version, but that does get you lots of standard equipment. Citroen’s miniature SUV also has plenty of other things to like besides, such as its bold styling, quirky character and smooth driving manners.
Citroen C3 Aircross Review
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The Best Green Self-Charging Hybrid Cars
1. Mazda 2 Hybrid 1.5 116
WLTP Fuel Consumption: 74.3mpg
If you’re thinking that the Mazda 2 Hybrid looks a lot like the Toyota Yaris then don’t worry, you haven’t gone stark-raving bonkers. In fact, the 2 Hybrid is little more than a rebadged version of the Yaris, built by Toyota alongside the Yaris, and then sold on to Mazda for resale to you. Given that the two cars are pretty much identical, we’re not entirely sure why official tests give the Mazda a fuel consumption figure that’s over 4mpg better than the Toyota’s, but we’re sure that the WLTP folks know what they’re doing. Bearing in mind their similarity, it’ll come as no surprise that the Mazda has many of the same attributes as the Yaris, which includes decent practicality, very solid build quality and agile, alert handling. However, while you’re also likely to enjoy the same stellar reliability as you will with the Yaris, do bear in mind that the Mazda only gets a three-year, 60,000-mile warranty.
Mazda 2 Review
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2. Toyota Yaris 1.5 VVTi 116
WLTP Fuel Consumption: 70.6mpg
The Yaris is a nameplate that’s been with us since the 1990s, and which offers self-charging hybrid tech in its latest incarnation. In fact, unless you go for the fire-breathing high-performance GR Yaris hot hatch (which actually bears very little mechanical resemblance to the regular car), then a hybrid-powered Yaris is the only Yaris you can have. And that’s no huge surprise. After all, no mainstream car company has as much experience with hybrid cars as Toyota: the original Toyota Prius was the world’s first mass-produced hybrid, and petrol-electric power now features in the vast majority of Toyota/Lexus models. And the hugely impressive efficiency figures of the Yaris are an indication of the brand’s peerless expertise in this area. That expertise should also mean that the technology is as reliable as every other bit of a Toyota has proved to be, and that’s hammered home by the backup of a warranty that could last for up to 10 years, provided that you get it serviced according to schedule at a main Toyota dealer and don’t bust the 100,000-mile cap.
Toyota Yaris Review
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3. Renault Clio 1.6 E-Tech
WLTP Fuel Consumption: 67.3mpg
This chic French supermini has kept itself fresh and relevant over the years by evolving through five generations, iterating and improving along the way, and the latest version is packing an impressive self-charging hybrid system. With a total of 143bhp to call upon from the combination of its 1.6-litre petrol engine and electric motor, this is the quickest Clio there is, and with an official fuel return of 67.3mpg, it’s also the cleanest. The latest Clio, first released in 2019, also received an extensive facelift in 2023 to bring the styling into line with newer models in the Renault range, and it looks a lot fresher as a result, both inside and out. The interior is spacious, nicely finished and well equipped, while the driving experience is generally very grown-up and relaxed, with a comfortable ride and good refinement.
Renault Clio Review
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The Best Green Plug-in Hybrid Cars
1. Mercedes-Benz GLC 300 de
WLTP Fuel Consumption: 706.3mpg
As impressive as both the Mercedes saloons listed below are in terms of their WLTP efficiency figures, neither can hold a candle to the GLC 300 de. This may be a bulkier, less aerodynamic car, but it has a different powertrain to its stablemates that more than makes up for the less slippery shape. Instead of a 2.0-litre petrol engine, it uses a 2.0-litre four-cylinder diesel engine to complement its electric motor, making the car capable of sprinting from 0-62mph in the same 6.4 seconds as it takes the E-Class PHEV. Crucially, though, the better mpg you get from a diesel, plus the GLC’s larger 31.2kWh battery that gives it an all-electric driving range of up to 84 miles, contributes towards a staggering official WLTP fuel economy figure of 706.3mpg. Just like with any plug-in hybrid, we’d recommend extreme caution with these figures, as the WLTP testing process is unrealistically flattering to plug-in hybrids: the figure you get in the real world will depend entirely on how much of your motoring you can complete on electric-only power. Still, the figures are hugely impressive nonetheless.
Mercedes-Benz GLC Review
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2. Mercedes-Benz E 300 e
WLTP Fuel Consumption: 565.0mpg
Given the similarity of its name, it’ll come as no surprise that the E300 e has exactly the same petrol-electric powertrain as its C-Class stablemate below. That means the same prodigious 309bhp power output, although due to the bigger, heavier body of the E-Class executive saloon, it’s a fraction slower, taking an extra 0.3 seconds to sprint from 0-62mph. However, we’ve given the E-Class the edge over the C-Class in this list because according to the official figures, although it has an identical fuel economy figure of 565.0mpg, it’ll apparently go a mile further (71 miles) on electric-only power: confusing when it’s a heavier car with an identical battery, but the numbers are the numbers. The E-Class also gives you even more practicality and an even plusher interior, while the on-board tech is just as impressive.
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3. Mercedes-Benz C 300 e
WLTP Fuel Consumption: 565.0mpg
You don’t need to be Sherlock Holmes to notice a pattern in this part of our list. It would appear that, when it comes to plug-in hybrids, nobody makes more efficient ones than Mercedes-Benz. The last in this three-car rundown of Mercedes’ plug-in-hybrid greatest hits is the C-Class saloon, namely the C 300 e. The combination of its 2.0-litre four-cylinder petrol engine and its electric motor gives this plug-in executive car a whopping 309bhp, making it capable of seeing off the 0-62mph dash in just 6.1 seconds, so it’s no slouch. More importantly for the purposes of this list, though, is that the car’s 25.4kWh lithium-ion battery pack gives it a hugely impressive electric-only range of 70 miles, and that contributes to a WLTP fuel economy figure of 565.0mpg. Chuck in the roomy, plushy trimmed cabin and the excellent infotainment technology on board, and that’s a very appealing package.
Mercedes-Benz C-Class Review
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The Best Green Electric Cars
1. Tesla Model 3 57.5kWh
EVDB consumption: 4.52m/kWh
For a long time now, the Tesla Model 3 has been the poster-child for the mainstream EV movement: sure, it was the Model S and Model X that made electric motoring cool and desirable, but it was the Model 3 that made that desirability genuinely affordable and attainable. Today, it’s still one of the most popular EV choices there is, and that’s because beneath all the hype lies a car of real substance. It’s fun to drive, it goes like the clappers, and it has the kind of gadgetry - not least in the infotainment and autonomous driving departments - that will have tech-fans coming back for more time after time. The fact that the Electric Vehicle Database data puts it on top in the efficiency stakes adds an extra layer to its appeal, alongside its impressive range figures and the firm’s brilliant Supercharger network that further reduces charging headaches on long journeys.
Tesla Model 3 Review
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2. Hyundai Ioniq 6 Long Range 2WD
EVDB consumption: 4.12m/kWh
The data from Electric Vehicle Database puts the Hyundai Ioniq 6 in second spot. Few car companies have been as proactive in the mainstream EV market as Hyundai in the last few years, and not only has the Korean firm come up with a broad choice of models, but they’ve also been some of the most eye-catching and interesting offerings anywhere on the market. The Ioniq 6 is perhaps the most interesting of the lot. It uses the same platform and running gear as the smaller, boxier Ioniq 5, but its aerodynamic ‘Streamliner’ shape helps it shine on the efficiency front, as its inclusion here shows. Sure, the ride is a bit on the firm side and the interior is a little short on quality in a few places, but the Ioniq 6 is much roomier inside than it looks, and it comes absolutely packed with cutting-edge tech.
Hyundai Ioniq 6 Review
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3. Vauxhall Corsa Electric 51kWh
EVDB consumption: 4.05m/kWh
Vauxhall has offered an electric version of the Corsa supermini for some years now, but in 2023, that car was facelifted and overhauled. This brought not only sharper looks and a new name (it changed from being the Corsa-e to the Corsa Electric), but a new long-range variant was also introduced, featuring a new battery pack with improved cell technology, plus an extra 20 horsepower. It’s that upgraded version that makes our list, with a return of just over four miles per kilowatt hour according to data from the Electric Vehicle Database. The Corsa Electric is an appealing car in other ways, too. It feels very grown-up for a car of its size, with a comfortable ride, great refinement and a soberly styled and well-made interior. It’s not the roomiest car of its type, nor is it the most enjoyable to drive, but otherwise, it is an extremely good all-rounder.
Vauxhall Corsa Review
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(Note: Information correct at time of publication, but is subject to regular change and so should be independently verified.)