7kW vs 22kW EV charger comparison: Is it worth installing a 22kW system?

When choosing a home EV charger, you'll often see both 7kW and 22kW options mentioned. While faster sounds better, the reality is more nuanced. Here's everything you need to know to make the right choice.

The Key Difference: Single-Phase vs Three-Phase

7kW Charger (Single-Phase)

Works with standard UK single-phase electricity supply

Available to virtually every UK home

Maximum charging speed: 7.4 kW (32A × 230V)

Adds approximately 25–30 miles of range per hour

22kW Charger (Three-Phase)

Requires a three-phase electricity supply

Only available to ~5% of UK homes (mostly new builds and rural properties)

Maximum charging speed: 22 kW (32A × 400V × 3)

Adds approximately 80–90 miles of range per hour

The bottom line: Unless you already have three-phase power, a 7kW charger is your only practical option — and it's all most drivers need.

Do You Have Three-Phase Power?

Most UK homes have single-phase electricity. You might have three-phase if:

Your property was built recently (some new developments include it)

You live in a converted commercial building

You've had three-phase installed for other equipment (workshops, farms)

Your consumer unit has three rows of breakers

How to check: Look at your main fuse and incoming supply. A single-phase supply has one live wire; three-phase has three (usually red, yellow, blue or brown, black, grey).

Can You Upgrade to Three-Phase?

Yes, but it's expensive:

Cost: £3,000–10,000+ depending on distance from the nearest three-phase supply

Process: Application to your Distribution Network Operator (DNO)

Timescale: Several weeks to months

Worth it for EV charging alone? Rarely

Unless you need three-phase for other reasons (large workshop, heat pump, multiple EVs), upgrading solely for faster home charging doesn't make financial sense.

Charging Speed Comparison

Battery Size	7kW Charger (20–80%)	22kW Charger (20–80%)
40 kWh	3.5 hours	1 hour
60 kWh	5 hours	1.5 hours
80 kWh	7 hours	2 hours
100 kWh	8.5 hours	2.5 hours

The Car's Limitation: Onboard AC Charging Speed

Here's the crucial factor many people overlook: your car's onboard charger limits AC charging speed, regardless of how fast your home charger is.

Onboard AC Charging Limits by Vehicle

Vehicle	Max AC Charging	22kW Charger Actual Speed
Tesla Model 3/Y (UK)	11 kW	11 kW (not 22 kW)
VW ID.3/ID.4	11 kW	11 kW
BMW iX	11 kW	11 kW
Hyundai Ioniq 5	11 kW	11 kW
Kia EV6	11 kW	11 kW
Renault Zoe	22 kW	22 kW ✓
Mercedes EQS	22 kW	22 kW ✓
Polestar 2	11 kW	11 kW

Key insight: Most popular EVs in the UK are limited to 7–11 kW AC charging. A 22kW home charger would only charge at 11 kW (or 7 kW for some models) anyway.

Cost Comparison

7kW Charger Installation

Charger unit: £400–800

Installation: £300–600

Total: £700–1,400 (or less with grants)

22kW Charger Installation (if you have three-phase)

Charger unit: £800–1,500

Installation: £500–1,000

Total: £1,300–2,500

Three-Phase Upgrade + 22kW Charger

Three-phase installation: £3,000–10,000

Charger + installation: £1,300–2,500

Total: £4,300–12,500

Who Should Consider a 22kW Charger?

A 22kW charger makes sense if:

1You already have three-phase power — no upgrade cost

2Your EV accepts 22kW AC charging — currently rare in the UK market

3You need very fast home charging — perhaps for business use or high daily mileage

4You're future-proofing — expecting to buy a 22kW-capable EV

5You have multiple EVs — some 22kW chargers can split power between two cars

Why 7kW Is Enough for Most Drivers

Consider typical driving patterns:

Average UK Driver (30 miles/day)

Uses ~10 kWh daily

7kW charger replenishes this in ~1.5 hours

Full overnight charge = 50+ kWh = 150+ miles

High-Mileage Driver (100 miles/day)

Uses ~30 kWh daily

7kW charger replenishes this in ~4.5 hours

Still easily achievable overnight

The "I forgot to plug in" scenario

Need 100 miles of range before leaving

7kW charger: 3–4 hours

22kW charger: 1–1.5 hours

Reality: public rapid charging solves this faster anyway

Three-Phase Alternatives

If you need faster home charging but don't have three-phase:

1. Multiple 7kW Chargers

One charger per EV in a multi-car household

Both cars can charge simultaneously

Often cheaper than upgrading to three-phase

2. Dynamic Load Management

Allows full-speed charging when household demand is low

Can charge faster during overnight hours when other appliances are off

3. Use Public Rapid Chargers When Needed

50–350 kW public chargers are widely available

20 minutes can add 100+ miles

Best for occasional urgent top-ups

Environmental and Grid Considerations

Interestingly, slower home charging can be better for the electricity grid:

Lower peak demand: 7kW spread over more hours vs 22kW concentrated

Smart tariff compatibility: More time to use off-peak electricity

Grid stability: Helps balance renewable energy supply

Our Recommendation

Choose a 7kW charger if:

You have single-phase power (most UK homes)

You drive a typical EV with 7–11 kW AC charging

You charge overnight while sleeping

You want the most cost-effective solution

Choose a 22kW charger if:

You already have three-phase power

Your EV supports 22kW AC charging

You need the fastest possible home charging

You're installing for a business or fleet

Don't upgrade to three-phase just for EV charging

The £3,000–10,000 cost is rarely justified. That money is better spent on:

A quality 7kW smart charger

Solar panels (to offset charging costs)

An EV tariff (7p/kWh overnight electricity)

Summary

Factor	7kW Charger	22kW Charger
Works with single-phase?	Yes	No
Typical UK home compatible?	Yes	~5%
Overnight charging sufficient?	Yes	Yes
Most EVs can use full speed?	Yes	No (limited to 7–11 kW)
Installation cost	£700–1,400	£1,300–2,500+
Best for	Most drivers	Three-phase homes

For the vast majority of UK EV owners, a 7kW charger provides everything you need at a fraction of the cost. Save your money — or invest it in a smart tariff that cuts your charging costs instead.