New EV efficiency ratings reveal most efficient electric cars

While we often check how many miles per gallon a petrol or diesel vehicle can do, we’re less likely to examine the efficiency of an electric vehicle (EV) – simply assuming they’re more environmentally friendly.

Now Electrifying.com has launched a new ‘E-Rating’ system to inform British buyers about how efficiently EV models use electricity, as well as make them aware of the £500 gap in annual charging costs between the best and worst cars.

Of the 49 models already rated by the media platform and EV consumer site, the BMW i4 and Tesla Model 3 have the highest rating, A++. The 13 models that follow have an A+ rating, including the Hyundai Ioniq 5, Vauxhall Corsa-e and electric Fiat 500.

Each EV’s rating is calculated using an algorithm that takes various factors into consideration, such as how well electrical energy is converted into miles on the road and the speed at which the battery can be charged. It also looks at features like heat pumps, intelligent brake energy recuperation and climate control preconditioning, which can all minimise energy use.

Based on kWh – a measure of how much energy is being used per hour – Electrifying estimates that an A++ car like the BMW i4 would cost £580 less over 10,000 miles than a model in grade E.

Whilst this comparison is drawn between models not competing in the same segment, there are still savings to be made between two direct rivals. For instance, a tesla Model Y can save you £180 over the same period compared with a Volvo XC40 Recharge.

Some vehicles also take longer to charge than others, with a Vauxhall Mokka charging at twice the speed of a Mazda MX-30, for example, while some Hyundai and Kia models can add 60 miles of range in under five minutes.

• Electric cars – a definitive guide and tips for buyers
• Electric car charger type, connectors and speeds – a visual guide
• How long do electric car batteries last? EV battery recycling

Ginny Buckley, founder of Electrifying.com, said: “It amazes me that until now we haven’t had any effective efficiency standard for electric cars, as we do across other sectors; but we’ve looked to put this right.

“As electricity costs less than petrol or diesel, it is easy to dismiss the efficiency of electric cars and think it isn’t important. But the costs of a less efficient model can soon add up. Perhaps more importantly, an electric car that is more frugal will go further and spend less time charging, meaning greater convenience for consumers.”