7kW vs 22kW Home EV Charger: Which Do You Need?

You need a 7kW charger.

That's the answer for over 95% of UK households. If you want to know why, and the rare situations where 22kW makes sense, read on. But if you came here worried you'd picked the wrong one: you haven't.

The basics

The number (7kW, 22kW) is the power output. More power means faster charging. A 22kW charger is roughly three times faster than a 7kW.

But here's the thing. The charger's speed only matters if the rest of the chain can keep up. And in most UK homes, it can't.

Why your house almost certainly can't do 22kW

A 7kW charger runs on single phase electricity. That's the standard supply to virtually every home in the UK: 230 volts, one live conductor.

A 22kW charger needs three phase electricity: 400 volts, three live conductors. Most UK homes don't have this. Over 95% of residential properties run on single phase.

You might have three phase supply if you live in a larger detached property, a rural home with an upgraded connection, or a property that once had a workshop or industrial equipment. You'd know, because your consumer unit would look different and your electrician would have mentioned it.

If you don't have three phase supply and want it, your DNO can upgrade you. The cost: £3,000 to £15,000, depending on how close you are to the nearest three phase network. For the sole purpose of faster home charging, that's not a rational investment.

How the speeds compare

Most people drive 20 to 40 miles a day. A 7kW charger, plugged in when you get home, replaces that in 1 to 2 hours. Overnight, it fully charges the battery from any state. Unless you're regularly arriving home with a dead battery and leaving again three hours later, 7kW is more than enough.

Your car might not even use 22kW

Even if you have three phase supply and install a 22kW charger, your car has its own speed limit. Every EV has an onboard AC charger that caps how fast it can accept power from a home charger.

The Renault Zoe is the notable exception with a full 22kW onboard charger. Most popular EVs sold in the UK cap at 11kW AC. A 22kW home charger plugged into a Tesla Model 3 charges at 11kW. You'd be paying for a capability your car can't use.

The cost difference

If you already have three phase, a 22kW charger costs a few hundred more. Marginal. But if you need the supply upgrade, you're looking at £4,000 to £16,000 total for the privilege of charging faster while you sleep.

When 22kW actually makes sense

There are legitimate use cases. They're niche.

• You already have three phase supply and you drive a Renault Zoe or a future EV with a 22kW onboard charger. The charger itself costs only a bit more. Might as well.
• You run a business from home and need to charge multiple vehicles quickly during the day.
• You have a very long daily commute (100+ miles) and need a fast turnaround at home. Though even here, 7kW overnight probably covers it.

For everyone else, 22kW is a solution looking for a problem.

What about future proofing?

The argument for 22kW is usually "future proofing." As EVs get bigger batteries and higher onboard charger ratings, won't you want faster home charging?

Probably not. The industry is moving in two directions: smart 7kW to 11kW charging at home (where speed doesn't matter because you charge overnight) and ultra rapid 100kW+ DC charging on route (where speed does matter). Nobody is building a future around 22kW home charging.

The grid can't support it either. If every home on a street ran a 22kW charger simultaneously, the local transformer would struggle. DNOs know this. The push is toward smart, managed home charging at 7kW, not faster.

The verdict

Get a 7kW smart charger. Pair it with a smart energy tariff like Octopus Intelligent. Charge overnight at the cheapest rate. That's the setup that saves you the most money and covers virtually any driving pattern.

If someone tells you that you need 22kW at home, ask them two questions: do you have three phase supply, and can your car actually charge at 22kW? If the answer to either is no, save your money.