Updated energy price cap: annual cost of charging an electric car at home will rise by average of £165

***UPDATE: The new Energy Price Guarantee (EPG) announced on 8 September will replace the previously announced price cap of £3,549/52p per kWh. The EPG means electric cars will continue to be cheaper to fuel than petrol and diesel equivalents. Taking effect as of October 1, we have updated all the figures in the story to reflect the EPG.***

The cost of charging an electric car at home will rise on October 1, though not as significantly as originally thought.

From 1 October, for customers paying for variable tariffs by direct debit in England, Scotland and Wales, unit rates and standing charges will work out at around 34p per kWh with a standing charge of 46p per day.

This is an increase on the current average unit of 28p per kWh, but a lot less than the initial price cap announced in August of £3,549, or 52p per kWh.

Had people paid 52p per kWh, it would have meant that over half the electric cars we've tested would become more expensive to charge with electricity at home (on a variable tariff) compared to running the same sized car on diesel.

The updated Energy Price Guarantee (EPG) fixes that situation. With an average 34p per kWh rate for electricity, EVs will continue to save large amounts of money on fuel bills when compared to cars running on petrol and diesel.

However, those who are not fortunate enough to be able to charge from home, or otherwise rely heavily on the public EV charging network, will often pay more than petrol/diesel cars.

Electric car reviews you can trust

What is the Energy Price Guarantee and how does it affect me?

On 9 September, the government announced a new two-year energy price guarantee (EPG) of £2,500 for a 'typical household' paying by direct debit, replacing the £3,549 price cap that had been due to come into effect from 1 October. 

However, the cap is on the price of a single unit of energy, not your total bill. What you actually pay personally will depend on how much you use. Understanding the unit rates is a clearer way of understanding what the EPG means for your bills.

Find out more about the EPG and how your household bills will change by heading to our EPG guide and tool. 

Buying electric? Miles per kWh is key

In the world of internal combustion, most people would naturally expect a small, low-powered city car to cost you much less to run than a massive four-wheel-drive SUV with a powerful engine.

The same is true of electric cars, and an efficient EV can save you hundreds of pounds per year compared to those that are hungrier for power.

But whereas the economy of a combustion powered car is indicated by its average MPG (miles per gallon), an electric car’s energy consumption is measured in miles per kWh (mi/kWh), ie how many miles you get for every kWh you have in your battery.*

And the same generalisations remain true: smaller, lighter electric cars are, on average, more economical than large SUVs and people carriers. Our table below shows how a car’s size has an effect on how much energy the car needs to run, and the subsequent cost of charging it from home.

*Figures shown to two decimal places for ease of reading

**8,100 miles is the average annual mileage as reported by consumers in our 2022 car survey

Electric cars no longer more expensive to run than diesel

Had the planned price cap of 52p kWh gone ahead, there would have been several car classes where it would have been cheaper to fill a car with diesel compared to charging an EV electricity at home.

However, with the EPG now replacing the cap, electric cars across all classes will remain cheaper than diesel, as our table shows:

*Figures shown to two decimal places for ease of reading

**8,100 miles is the average annual mileage as reported by consumers in our 2022 car survey

***Cost per litre taken from RAC Fuel Watch on 26 August.

Taking medium-sized cars as an example (think cars like the VW Id.3 or Ford Focus), the average medium-sized electric car would have been £158 more expensive than the same sized diesel car under the 52p per kWh cap. But the EPG means it will still save over £300 a year compared to diesel, ensuring EVs remain reassuringly less to fuel - at home at least.

Rapid public charging still overtaking petrol and diesel costs

Prior to the news of the price cap, a number of charge point operators – which are also facing the same unprecedented rise in energy costs – raised their prices or announced they were about to do so.

Some networks that provide ‘rapid’ charging, which use high-powered chargers (50-350kW) to charge a car as fast as possible, charge in excess of 60p per kWh.

Depending on the car, our research shows that if you’re paying more than 47p per kWh, you’re paying more than you would be in an equivalent petrol or diesel car. So at over 60p per kWh, you could be paying substantially more to charge your car with electricity than you would to run the same size car on diesel or petrol.

One reason for prices being so much higher away from home is that electricity at home is subject to 5% VAT, whereas public charging networks have to charge 20% VAT.

Popular network Instavolt raised its prices for its rapid chargers to 66p per kWh as of 15 August, but states that if they were able to charge 5% VAT, that cost would be 58p per kWh.

The VAT rate is not up to the charge point operator. The government would have to decide to lower VAT to 5%, but has previously ruled this out. 

Fiat 500e Cabriolet (2020-)

• Class: City car
• Equivalent power: 118hp
• Battery capacity: 37.3kWh
• Efficiency in Which tests: 3.58mi/kWh

• Cost of charging at home (new price cap – 34p per kWh): 9.5p per mile
• Cost of charging publicly (55p per kWh): 15.4p per mile
• Equivalent-sized petrol car running cost: 15.6p per mile
• Cost of charging publicly (60p per kWh): 16.8p per mile
• Cost of charging publicly (65p per kWh): 18.2 per mile

The Fiat 500e cabriolet is not without its compromises but is one of the most efficient electric car’s we’ve tested.

Find out what the compromises are by reading out Fiat 500e Cabriolet (2020-) review.

Hyundai Ioniq 5 (2021-)

• Class: Large car
• Equivalent power: 217hp
• Battery capacity: 72.6kWh
• Efficiency in Which? tests: 2.97mi/kWh

• Cost of charging at home (new price cap – 34p per kWh): 11.4p per mile
• Equivalent-sized petrol hybrid car running cost: 13.5p per mile
• Equivalent-sized diesel car running cost: 17.2p per mile
• Cost of charging publicly (55p per kWh): 18.5p per mile
• Cost of charging publicly (60p per kWh): 20.2p per mile
• Cost of charging publicly (65p per kWh): 21.9p per mile
• Equivalent-sized petrol car running cost: 22p per mile

The Ioniq5 is an electric car that’s as fantastic as its looks suggest. With the EPG, the cost of charging this car is comfortably below other fuel types of the same sized car, including the typical petrol-hybrid.

Here’s our full test of the Hyundai Ioniq5 (2021-).

Volkswagen ID.4 (2021-)

• Class: Mid/Large SUV
• Equivalent power: 204hp
• Battery capacity: 77kWh
• Efficiency in Which? tests: 2.73mi/kWh

• Cost of charging at home (new price cap – 34p per kWh): 12.5p per mile
• Equivalent-sized petrol-hybrid SUV running cost: 16.9p per mile
• Equivalent-sized diesel SUV running cost: 20.1p per mile
• Cost of charging publicly (55p per kWh): 20.2p per mile
• Equivalent-sized petrol SUV running cost: 20.4p per mile
• Cost of charging publicly (60p per kWh): 22p per mile
• Cost of charging publicly (65p per kWh): 23.9p per mile

The ID.4 is a mid-sized all-electric SUV. A spacious and appealing family car, it managed a decent range in our tests. There is also a sportier version, the ID.4 GTX, but naturally that’s a bit less efficient. Compared to diesel and petrol equivalents, the regular ID.4 will save you hundreds of pounds per year if you're able to charge from home.

Looking for a zero emission family car? Read our Volkswagen ID.4 (2021-) review.

Mercedes-Benz EQV (2020-)

• Class: Large people carrier
• Equivalent power: 204hp
• Battery capacity: 90kWh
• Efficiency in Which? tests: 2.01mi/kWh

• Cost of charging at home (new price cap – 34p per kWh): 16.9p per mile
• Equivalent-sized diesel MPV running cost: 18.3p per mile
• Cost of charging publicly (55p per kWh): 27.4p per mile
• Cost of charging publicly (60p per kWh): 29.8p per mile
• Cost of charging publicly (65p per kWh): 32.3p per mile

The Mercedes-Benz EQV might be the least efficient electric car we’ve tested to date, but it will still save you money compared to large people carrier that runs on diesel.

Looking for a luxury all-electric people carrier? Mercedes-Benz EQV (2020-) review.

Our guides on charging an electric car explain everything from how long it takes to charge an electric car, to charging at home and using the public charging infrastructure. 

We’re working to make EV life simpler, from calling on manufacturers to add AC and DC charge rates to cars, to making payments easier and improving charge point reliability. Read more about our vision for an EV future by heading to our paper on Building an Electric Vehicle Charging Infrastructure that is Fit for the Future.

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*Energy efficiency can also be shown as kWh/100km – the kWh needed to drive 100km, or 62 miles. Our reviews show our independent test figures in both mi/kWh and kWh/100km forms.

Article edited at 15:01 (26 August) to correct statistic about compact/small SUVs and medium car running costs.

Article edited at 07:13 (2 September) to correct hybrid, petrol and diesel pence per mile figures.

Article edited at 16:15 (12 September) following the EPG announcement.