7kW vs 11kW vs 22kW home EV chargers: what the numbers mean

Why 7kW, 11kW and 22kW appear on chargers

Home EV chargers are commonly sold with maximum output ratings of 7kW, 11kW or 22kW, describing how much power the charger can deliver to a compatible vehicle. In practice, the actual charging speed you get also depends on your home's electricity supply and the vehicle's onboard charger, not the charger unit's rating alone.

Single-phase versus three-phase supply

The great majority of UK domestic properties have a single-phase electricity supply, which practically limits a home charger to a maximum of around 7kW. This is simply a characteristic of how the electricity is supplied to the property, not a choice made by the charger manufacturer.

11kW and 22kW chargers generally require a three-phase electricity supply to deliver their full rated output. Three-phase supplies are uncommon in typical UK homes and are more often found in some larger properties, rural areas, or commercial premises. Installing a three-phase supply where one does not exist usually involves contacting the local electricity distribution network operator (DNO) and can be a substantial, costly undertaking.

Your vehicle's onboard charger also sets a limit

Electric vehicles have an onboard charger that converts the AC electricity from a home charge point into DC electricity to charge the battery. This onboard charger has its own maximum power rating, commonly 7.4kW or 11kW on many current models, and the vehicle cannot charge faster than its onboard charger allows, regardless of how powerful the home charger is.

This means installing a higher-power charger than your vehicle can actually use will not speed up charging for that vehicle, though it may be a reasonable choice if you expect to own a vehicle with a higher onboard charger limit in future.

What this means for practical charging times

As a broad illustration only, a 7kW charger can add roughly 30 kilometres of range per hour of charging for a typical family-sized electric car, though this varies by vehicle efficiency and is not a guaranteed figure. Overnight charging on a 7kW charger is generally sufficient to fully charge most home electric vehicles from a low state of charge.

For most households using their car for daily commuting and occasional longer trips, a 7kW charger paired with overnight charging comfortably covers typical usage patterns.

Charging speed figures here are illustrative only and vary by vehicle model, battery size, and temperature. Check your specific vehicle's onboard charger rating and manufacturer guidance.

Checking what your home can actually support

Before assuming you can or should install an 11kW or 22kW charger, ask your installer to check your property's electricity supply type and capacity, and confirm with them whether any DNO notification or approval is needed for the installation you want.

For the large majority of UK homeowners with a standard single-phase supply, a 7kW charger paired with a compatible vehicle remains the realistic and most cost-effective choice.