EV home charging explained: how home chargers work, how much they cost and the grants available

Mercedes-Benz has become the latest car maker to announce that it will move to an all-electric range by 2030.

It joins the likes of Jaguar, Mini, Vauxhall and Volvo as manufacturers react to impending bans on petrol and diesel cars around the world.

While the UK’s ban on new ICE cars won’t mean we’re all driving EVs by 2030, they will be a far more common choice for motorists, bringing new challenges and opportunities.

Much of the debate around EVs at the moment is around whether the UK’s public charging infrastructure will be ready for large-scale transition. Questions over the number and reliability of public chargers along with their speed and price are a constant hot topic.

However, these arguments ignore the estimates that EV owners do 80 per cent of their charging at home, relying on public sites for top-ups on longer journeys.

With home charging such a key element of EV ownership, it’s important to understand what it entails, from the hardware to speed and cost, so here’s a beginners guide on everything from charging speeds to government grants.

What is a wallbox?

Wallbox is the industry term for a purpose-made EV charger fitted at your home or place of work. Usually these are fitted to the external wall of your house or garage but can also be fitted internally in a garage or mounted on a free-standing post.

The benefit of these standalone chargers is that they will charge an EV far faster than a standard domestic plug socket - up to three times faster. They are also weatherproof and a far neater solution than trailing a cable out of a garage door or window.

Types of home charger

There are a few key variables when considering a wallbox, chiefly speed, tethering and whether it is “smart” or “dumb”.

Speed

All home wallboxes will use an AC supply and most will be 3kW or 7kW, referring to the speed they can charge at. A 3kW charger is referred to as a “standard” or “slow” charger, the 7kW as a “fast” charger.

You can also get 11kW or 22kW AC charging but this requires three-phase wiring usually only found in commercial or industrial premises.

A 3kW charger will take around 17 hours to fully charge a 50kWh Renault Zoe. A 7kW wallbox cuts this to just under seven hours, while a 22kW unit will take just over two hours.

Tethered or untethered

Wallboxes are sold as tethered or untethered. Tethered come with a charging cable preinstalled. This is fine if you are only charging one EV but could potentially cause problems if you later change car. Untethered or universal wallboxes feature a Type 2 socket into which you can plug any modern AC charging cable.

Smart chargers

Smart chargers are internet-connected units that can be programmed and controlled via a mobile app, relay charging data and take advantage of preferential energy rates.

Most modern chargers now feature smart functions after funding changes meant they were the only ones eligible for a government grant.

How much do home chargers cost?

The price of a home wallbox is determined by various factors including its speed, whether it has connected smart features and even its design. Even where you live can have an impact on the final cost.

Prices start at around £700-£800, rising to well over £1,000 but those are before the government grant or any offers from a car maker. The standard government Plug-in Car Grant (PiCG) brings basic units down to around £450-£500.

Tethered units are usually more expensive than untethered and sleeker designs will cost more. Smart chargers appear more expensive than “dumb” ones on paper but are they only kind eligible for the OLEV grant (see below).

Installing the charger is usually included in the price, as long as you use one of the manufacturer’s recommended installers. However, if the installation is particularly complicated or you live somewhere remote, you might have to pay more.

Some car makers also offer a contribution towards the cost or will supply a free wallbox to buyers of their EVs.

EV charger grants

To encourage uptake of EVs, the UK Government offers a grant towards the installation of a wallbox via the Office of Zero Emission Vehicles (OZEV).

The Electric Vehicle Homecharge Scheme (EVHS) will pay 75 per cent of the cost of a wallbox and installation, up to a maximum of £350.

You can check car eligibility, approved chargers and installers and apply for the grant here.

In Scotland, the Energy Saving Trust will provide up to £300 further funding on top of this, with an additional £100 available for those in the most remote parts of Scotland.

How much does charging cost?

Charging costs are determined by your home electricity tariff. The average rate in the UK is 14.4p per kWh. To fully charge a model like the 50kWh Renualt Zoe would cost around £7.20.

However, many energy companies offer EV tariffs with cheaper nighttime rates. These allow you to charge overnight for as little as 4.5p per kWh. Earlier this year Ovo also launched a smart tariff that claims to offer a 6pp KWh type-of-use tariff specifically for EVs.

Some car makers, energy providers and charging firms also offer “free miles” to buyers. This usually takes the form of a refund on household electricity when you sign up to a particular tariff but can also take the form of free access to certain public chargers.

Can I use a regular domestic plug socket?

You can use cable fitted with a regular 13A three-pin plug to charge an EV but it’s generally recommended only as a last resort. Most manufacturers recommend you have a wallbox fitted and some don’t even supply a three-pin cable as standard.

It is referred to as trickle charging and a Renault Zoe with a 50kWh battery will take more than 29 hours to charge, compared with seven hours on a 7kW wallbox.