The short answer
For most UK homes, a 7 kW charger is the right choice: it adds around 25–30 miles of range per hour and charges a typical EV overnight on a standard single-phase supply. A 3 kW unit is slower but works on a dedicated 16 A circuit; 22 kW requires three-phase supply, which most homes do not have. See whether your electrics can handle it before deciding.
Charge point speed is measured in kilowatts (kW) — the higher the number, the more electricity delivered per hour and the faster the charge. In practice, three speeds matter for home use: 3 kW (16 A), 7 kW (32 A) and 22 kW (three-phase 32 A). Each has different implications for how quickly your car charges, what your home electrical supply needs, and what it costs to install. Most UK drivers do not need to agonise: 7 kW on a standard single-phase supply is the settled default, and it is the speed OZEV grants are designed around.
Charger speeds at a glance
- 3 kW (16 A) ~13 miles per hour — single-phase, smaller circuit
- 7 kW (32 A) ~25–30 miles per hour — single-phase standard home
- 22 kW (32 A) ~75 miles per hour — three-phase supply required
- Most UK homes Single-phase only — 7 kW maximum practical
- Overnight charge 7 kW fills most EVs in 6–10 hours
- Grant Available for qualifying 7 kW smart installs via OZEV
What the speed numbers mean in practice
The kW figure tells you how much power is flowing into the car. Divide your car’s usable battery capacity (in kWh) by the charger power (in kW) and you get a rough charge time in hours — though in practice the last 20% of charge is usually slower to protect the battery. A 77 kWh car (typical of a Volkswagen ID.4 or similar) on a 7 kW charger takes roughly 11 hours from near-empty to full, which fits neatly into an overnight window. On a 3 kW charger the same car takes around 25 hours.
| Charger speed | Miles added per hour | Hours to charge 60 kWh EV | Supply required |
|---|---|---|---|
| 3 kW (16 A) | ~10–13 miles | ~20–25 hours | Single-phase 16 A |
| 7 kW (32 A) | ~25–30 miles | ~9–11 hours | Single-phase 32 A |
| 22 kW (32 A x3) | ~75 miles | ~3–4 hours | Three-phase 32 A |
Note that miles-per-hour figures are approximate: the actual rate depends on the car’s on-board AC charger limit (some cars cap at 3.7 kW or 11 kW regardless of the wall box), the battery’s state of charge and ambient temperature.
Why 7 kW is the standard for most UK homes
The vast majority of UK properties have a single-phase 100 A supply, which comfortably supports a 7 kW (32 A) dedicated charger circuit. Seven kilowatts is also the sweet spot for overnight charging: an average driver covers around 20–30 miles a day, which a 7 kW charger replaces in under two hours. Adding a smart unit lets you schedule that charge to the cheap off-peak rate — typically midnight to 5 am on specialist EV tariffs — which can cut charging costs significantly. The OZEV £350 grant is structured around this standard configuration. See the EV charger grant guide for eligibility.
When 22 kW makes sense
A 22 kW unit is worth considering only if your property already has a three-phase electricity supply (common in some larger or commercial premises, rare in typical UK homes) and your car’s on-board charger accepts 11 kW or 22 kW AC. Upgrading a single-phase property to three-phase costs thousands and involves work with your Distribution Network Operator, making it hard to justify for domestic EV charging alone. If you are not sure whether you have three-phase, an electrician can check at your consumer unit. Businesses, farms and larger premises are more likely candidates.
What about 3 kW?
A 3.7 kW (16 A) unit is occasionally installed where load management is a concern — for example, a property with a very limited supply headroom or a communal meter situation. It charges more slowly but the circuit is lighter. The OZEV grant requires a minimum 3.5 kW smart unit, so a 3.7 kW compliant charger is grant-eligible. However, for most drivers the slower charge speed is a daily frustration with no offsetting benefit. See load balancing for situations where a lower-output unit combined with dynamic load management might make sense.
Can your home supply handle it?
A qualified installer will check your consumer unit, the incoming supply capacity and any existing high-demand appliances before confirming the right circuit size. Most homes with a modern 80–100 A supply handle a 7 kW charger without issue, but older properties with a 60 A or smaller cut-out may need a supply upgrade. The home electrics guide covers this in detail. This page is general information; always have a qualified, OZEV-approved electrician assess your specific supply before choosing a charger speed.
Not sure which speed suits your home?
An OZEV-approved installer can check your supply, confirm the right charger power and apply the grant on your behalf. Free to enquire, no obligation.
Frequently asked questions
Is 7 kW fast enough for home EV charging?
For most drivers, yes. A 7 kW charger adds around 25–30 miles per hour, enough to fully replenish a typical EV overnight. The average UK driver covers around 20–30 miles per day.
Do I need three-phase supply for a 22 kW charger?
Yes. A 22 kW AC charger requires a three-phase electricity supply. Most UK homes are single-phase only, making 22 kW impractical without a costly supply upgrade.
Will a 22 kW charger charge my car faster than a 7 kW one?
Only if your car’s on-board AC charger accepts more than 7 kW. Many popular EVs are limited to 7 kW or 11 kW AC regardless of the wall box speed, so check your car’s specification first.
Is a 3 kW EV charger worth it?
Only in specific situations where supply headroom is very limited. Most installers recommend 7 kW as the sensible minimum for a home wall box, and it is what the OZEV grant is primarily aimed at.
Sources & further reading
- OZEV (Office for Zero Emission Vehicles) — EV chargepoint grant and speed eligibility guidance
- Energy Saving Trust — Home EV charging speeds and overnight charging guidance
- IET Wiring Regulations (BS 7671) — Circuit sizing and load calculations for EV charge points
- GOV.UK — Electric Vehicles (Smart Charge Points) Regulations 2021
This is general information about home EV charging in the UK, not electrical, planning or installation advice for your specific property. Costs, timescales and specifications vary with your home’s supply, parking arrangement and chosen installer. Always obtain written quotes from OZEV-approved installers and check grant eligibility at GOV.UK before committing.