7kW vs 22kW home charging: what's the difference?
Three times the power sounds like three times the speed, until the car and the street supply both say no.
The difference between 7kW and 22kW home charging is power and practicality: a 36kWh session takes about 5 hours at 7kW and about 1.6 hours at 22kW, but 22kW needs a three-phase electricity supply that most UK homes do not have, and most EVs limit AC charging to 7kW or 11kW regardless. For almost every UK household, a 7kW charger is the fastest sensible option.
How much faster is 22kW than 7kW?
On paper, three times faster: the same division as always. A typical 36kWh session (20% to 80% of a 60kWh battery) takes about 5 hours at 7kW and about 1.6 hours at 22kW.1 Per hour plugged in, that is roughly 24 miles of range against roughly 77 miles.
The catch is that the paper figure requires three things to line up, and in the UK they almost never do.
Why most UK homes cannot have 22kW
A 22kW charger needs a three-phase electricity supply: three live conductors instead of one, delivering 400 volts across phases. The overwhelming majority of UK homes, especially houses built after the war, have a single-phase supply. You can spot three-phase by the fatter service head at your meter with three fuses, but the definitive answer comes from your distribution network operator.
Upgrading to three-phase means new cabling from the street, a new meter and DNO involvement, typically a four-figure sum and a wait of weeks to months. Some installers quote several thousand pounds once groundworks are involved.2
Why most cars cannot use 22kW anyway
Home charging is AC, and AC charging speed is limited by the car’s onboard charger, not the wallbox. Most EVs sold in the UK cap AC charging at 7kW or 11kW: give them a 22kW supply and they politely take 7 or 11.1 Only a minority of models, mostly premium European cars, accept the full 22kW AC.
So the realistic outcomes of a 22kW installation are: single-phase home, charger delivers 7kW; three-phase home with a typical EV, delivers 7 or 11kW; three-phase home with a rare 22kW-capable EV, delivers 22kW. You are paying for the last scenario, which applies to very few driveways.
Does 11kW change the picture?
Barely, for homes. Some EVs accept 11kW AC, which needs a three-phase supply running at 16A per phase. If your home already has three-phase, an 11kW-capable charger trims a 36kWh session to about 3.3 hours instead of 5. Pleasant, but since both happen inside the same overnight window, it changes nothing you will ever notice. Where 11kW matters is at public AC chargers and workplaces, where three-phase is common and the car sits for hours rather than nights.1
How much does a three-phase upgrade cost?
Enough that you should get a quote before getting excited. The work involves your distribution network operator pulling a new three-phase cable from the street main, fitting a new cut-out and meter, and then your electrician upgrading tails and possibly the consumer unit. DNO charges alone commonly run into four figures once groundworks are involved, and timelines stretch to months.2 Set against the benefit (charging a 60kWh battery in 2.5 hours instead of 8.5, overnight, while you sleep), the return is hard to find for a single household car.
Does faster home charging save money?
No, and this point gets lost in the speed conversation. A kWh costs the same whether it arrives at 7kW or 22kW; faster charging buys time, not cheaper energy. The money in home charging comes from the tariff, specifically from charging inside off-peak windows at around 8p/kWh rather than the 26.11p/kWh cap rate. A 7kW charger inside a six-hour window delivers 42kWh at cheap rates, which covers a week of average commuting. Speed is rarely the binding constraint; the window is.3
What about load balancing and two EVs?
Two quieter technologies solve the problems people actually have. Load balancing lets a 7kW charger coexist with a small main fuse by throttling when the house draws heavily, avoiding a supply upgrade. And dual-socket chargers, or two chargers on a managed circuit, let a two-EV household share capacity: both cars charge overnight, each a little slower, both full by morning. For the two-car driveway, that setup beats a three-phase upgrade on cost by an order of magnitude.
Who should actually consider 22kW?
A narrow group: homes that already have three-phase (some larger or older properties, farms, converted commercial buildings), running a car that accepts 22kW AC, with a genuine need to refill big batteries in short daytime windows. A small business running two or three EVs off one three-phase supply can also make the case.
Everyone else: 7kW overnight is the answer. Ten hours asleep covers 70kWh, more than any mainstream EV battery, and the off-peak tariff rates that make home charging cheap all assume overnight windows anyway.3 If you regularly need speed rather than patience, that is what the UK’s 12,000-plus ultra-rapid public chargers are for.
For the full picture on home charging times, read how long it takes to charge an electric car at home.
- Key facts
- 36kWh session at 7kW
- About 5 hours
- 36kWh session at 22kW
- About 1.6 hours
- UK homes with 3-phase
- A small minority
- Typical EV AC limit
- 7 or 11kW
Sources
- ev-database.org, electric vehicle database Accessed 18 July 2026
- Alps Electrical, EV charger installation costs Accessed 18 July 2026
- Zapmap, EV charging statistics Accessed 18 July 2026