7kW vs 22kW home EV chargers: what actually makes sense for your house

Published 28 October 2026 · Data Lynes Electrical, Ruislip

The short answer

If you only take one thing from this post, let it be this: for almost every home in Ruislip, Pinner, Uxbridge and the rest of Hillingdon, a 7kW charger is the right choice — and not as a compromise. The 22kW units you see advertised are real, and they have their place, but that place is almost never a normal house. Here is why, in plain English.

Single-phase and three-phase, without the jargon

Electricity reaches your home through the supply cable in the street, and in the UK nearly every house gets a single-phase supply — one live conductor, which is ample for the way homes normally use power. Three-phase supplies, with three live conductors, are mostly found in commercial and industrial buildings, in the landlord supplies of some blocks of flats, and in the occasional very large house.

This matters because a 22kW charger needs three phases — it draws roughly 32 amps across each of them. A single-phase home simply cannot feed one. A 7kW charger, on the other hand, is designed around exactly what a single-phase supply can sensibly dedicate to a car: about 32 amps on the one phase you have. That is why 7kW has become the standard home charger across the country, and it is what we fit day in, day out on our EV charger installations around here.

Could I upgrade to three-phase?

Usually yes, technically. It means an application to your electricity network operator, a new supply arrangement, and often groundwork between the street and your house. What it costs and how long it takes varies so much from property to property that we will not pretend to give you a figure here — if you are curious, your network operator or your installer can look at your specific situation.

But in our experience it very rarely makes sense to do this just for car charging. Partly because of the upheaval, and partly because of a detail that surprises a lot of people: even with a 22kW charger on the wall, your car probably cannot use it.

Your car has a say in it too

Every EV has an onboard charger that converts the AC electricity from a home wallbox into the DC electricity its battery stores. The speed of home charging is capped by that onboard charger, not just by the box on the wall. Many EVs accept a maximum of around 7kW on AC; some manage 11kW; only a minority accept the full 22kW. Plug a 7kW-limited car into a 22kW wallbox and it charges at… 7kW.

If you are wondering how the same car gulps down 100kW or more at a motorway service station: rapid chargers are DC. They bypass the car’s onboard charger and feed the battery directly, which is a different system altogether and not something that exists in home form. It is worth checking your own car’s AC charging limit in its handbook before you let anyone talk you into chasing bigger numbers.

The overnight maths

Here is the sum that settles it for most households. A 7kW charger running for eight hours overnight can put up to roughly 50–56 units (kWh) of electricity into the car, allowing a little for losses. Most family EVs have batteries somewhere in the region of 50 to 80kWh — and crucially, most days’ driving only uses a modest slice of that. So a 7kW charger will comfortably top up a normal day’s driving in an hour or two, and take even a nearly empty battery to full, or close to it, while you sleep. Overnight also happens to be the window that many EV energy tariffs are built around, which is a happy coincidence.

Once you see it that way, the appeal of 22kW at home rather falls away. The car spends the night on the driveway either way; whether it finishes charging at 1am or 6am makes no practical difference to your morning.

So when does 22kW actually make sense?

On premises that already have a three-phase supply — workshops, offices, farms, some larger properties — paired with a car whose onboard charger can accept 11kW or 22kW AC. If that describes your place, it is a sensible conversation to have, and we are happy to have it. For everyone else, 7kW is not the budget option; it is the correct one.

Honest advice, locally

We are an NICEIC Approved Contractor based in Ruislip, working to BS 7671 (18th Edition) with a 12-month workmanship guarantee, and we install home chargers across Ruislip, Eastcote, Ickenham, Pinner, Northwood and the wider Hillingdon area. Every install starts with a look at your supply and your car, so you end up with the charger that suits your house — not the one with the biggest number on the box. And if you have no driveway at all, we have written a separate guide to EV charging without a driveway.

Thinking about a home charger, or just want a straight answer about your supply? Get in touch — we are happy to talk it through on the phone first.