When planning your home EV charger installation, one of the most important decisions you’ll face is choosing the right charging speed. Walk into any discussion about home charging and you’ll quickly encounter terms like 7kW, 11kW, and 22kW—but what do these numbers actually mean for your daily driving, and which speed do you genuinely need?
The difference isn’t trivial. A 22kW charger costs significantly more to purchase and install than a 7kW unit, but in many cases, you won’t actually benefit from that extra speed. Conversely, opting for a slower charger to save money could leave you frustrated if it can’t keep up with your charging needs.
This guide will help you understand charging speeds, calculate what you actually need based on your driving patterns, and make an informed decision that balances cost with practical requirements.
Understanding Charging Speed: The Basics
The kilowatt (kW) rating of your charger tells you how much power it can deliver to your car’s battery per hour. Think of it like filling a bathtub—a higher kW rating is like turning the tap on harder; the bathtub fills faster.
7kW charging adds approximately 25-30 miles of range per hour for most EVs. For a typical electric vehicle with a 60kWh battery, a full charge from empty takes about 8-10 hours.
11kW charging adds roughly 40-50 miles of range per hour, charging that same 60kWh battery in approximately 5-6 hours.
22kW charging can add 80-100 miles of range per hour, completing a full charge in around 3-4 hours—but there’s a significant catch we’ll discuss shortly.
These are approximate figures. The actual charging speed depends on several factors including your car’s battery size, its onboard charger capacity, battery temperature, and current charge level (charging typically slows as the battery approaches full).
The Reality Check: What Your Car Can Actually Accept
Here’s the crucial detail that many people overlook: your car’s onboard charger determines the maximum charging speed, regardless of how powerful your home charger is.
Most electric vehicles sold in the UK have onboard chargers that accept a maximum of 7kW or 11kW on single-phase power. Installing a 22kW charger won’t make these vehicles charge any faster—it’s like connecting a small garden hose to a fire hydrant; the hose is the limiting factor, not the water pressure.
Let’s look at some popular EVs and their maximum AC charging speeds:
7kW maximum (single-phase):
- Tesla Model 3 Standard Range: 7kW
- MG4 SE: 6.6kW
- Nissan Leaf: 6.6kW
- Renault Zoe (older models): 7kW
- Fiat 500e: 11kW (but only on three-phase, 7kW on single-phase)
11kW maximum:
- Tesla Model 3 Long Range/Performance: 11kW
- BMW i4: 11kW
- Mercedes EQC: 11kW
- Audi e-tron: 11kW
- Renault Zoe (newer models): 22kW (on three-phase)
22kW capable (three-phase only):
- Renault Zoe: 22kW
- Some Tesla Model S/X variants: 16.5-22kW
- Porsche Taycan: 11kW (22kW on three-phase where available)
The key point: even if you install a 22kW charger, if your car can only accept 7kW, you’ll charge at 7kW. Always check your specific vehicle’s specifications before deciding on charger speed.
Single-Phase vs Three-Phase Power: The Big Limitation
Most UK homes have single-phase electricity supply. This limits your maximum charging speed to 7kW (32 amps on a 230V single-phase supply).
Three-phase power supply is required for charging speeds above 7kW at home. Three-phase is common in commercial and industrial settings but relatively rare in residential properties. Some newer housing developments, rural properties, and homes that previously had commercial use may have three-phase supply, but the vast majority of UK homes do not.
If your home only has single-phase power (which you probably do), installing an 11kW or 22kW charger makes no sense—you’ll only ever charge at 7kW maximum, and you’ll have paid considerably more for hardware you can’t use.
How to check your supply: Look at your main electrical intake. Single-phase will have two main cables (live and neutral), while three-phase will have four (three lives and a neutral). If you’re unsure, your installer will assess this during the survey, or you can contact your Distribution Network Operator (DNO).
Can you upgrade to three-phase? Technically yes, but it’s expensive—typically £2,000-£5,000+ depending on your location and the work required. For most homeowners, this cost isn’t justifiable purely for faster EV charging.
Calculating What You Actually Need
Rather than guessing, let’s calculate your genuine requirements based on your driving patterns.
Step 1: Determine Your Daily Mileage
Think about your typical daily driving. For most UK drivers, this averages 20-30 miles per day. Even those with longer commutes rarely exceed 50-60 miles on a typical day.
Step 2: Convert Miles to kWh
Most modern EVs achieve approximately 3-4 miles per kWh efficiency. So:
- 30 miles per day = 7.5-10 kWh needed
- 50 miles per day = 12.5-17 kWh needed
- 100 miles per day = 25-33 kWh needed
Step 3: Calculate Charging Time at Different Speeds
At 7kW:
- 10 kWh (30 miles) = 1.5 hours
- 17 kWh (50 miles) = 2.5 hours
- 33 kWh (100 miles) = 5 hours
At 11kW (if you have three-phase):
- 10 kWh (30 miles) = 1 hour
- 17 kWh (50 miles) = 1.5 hours
- 33 kWh (100 miles) = 3 hours
At 22kW (if you have three-phase and your car supports it):
- 10 kWh (30 miles) = 30 minutes
- 17 kWh (50 miles) = 45 minutes
- 33 kWh (100 miles) = 1.5 hours
Step 4: Consider Your Available Charging Time
How long is your car parked at home overnight or during the day? For most people, this is 8-12 hours minimum.
If you need to charge 30 miles worth of range and you have 8+ hours available, a 7kW charger needs only 1.5 hours—you have more than enough time. Even if you drive 50 miles daily, the 2.5 hours required at 7kW fits comfortably within an overnight charging window.
When 7kW Is Perfectly Adequate
For the majority of UK homeowners, a 7kW charger is completely sufficient. This is true if:
Your daily mileage is under 100 miles—7kW will replace that range overnight without any issues.
You have regular overnight parking—with 8+ hours available, 7kW can fully charge most EVs from nearly empty.
You drive a typical EV with a 50-70kWh battery—these charge fully overnight at 7kW.
You have single-phase power—since you can’t charge faster anyway, paying for a higher-rated charger makes no sense.
Cost is a consideration—7kW chargers and their installation are the most affordable option.
The reality is that most EV owners plug in with 50-70% battery remaining (not completely empty) and need to top up 20-40 miles of range. At 7kW, this takes 1-2 hours—negligible when you’re home for the evening.
When You Might Need 11kW
There are legitimate scenarios where 11kW charging makes sense:
You have three-phase power supply already installed—if you already have three-phase, the additional cost for an 11kW charger over 7kW is modest.
Your EV supports 11kW charging—there’s no point installing 11kW capability if your car can only accept 7kW.
You regularly drive 100-150 miles per day—at 7kW, fully replenishing this range takes 5-7 hours. At 11kW, it’s 3-4 hours, giving you more flexibility.
You have limited charging time—if you can only charge for 4-5 hours overnight due to work patterns or off-peak tariff windows, 11kW helps you capture more range in that window.
You have multiple EVs in the household—faster charging means you can rotate vehicles through the charger more efficiently, though installing two 7kW chargers might be more practical.
When 22kW Makes Sense (Rarely for Homes)
22kW charging at home is rarely necessary or practical for most residential users. The scenarios where it’s justified are quite limited:
You have three-phase power AND your car accepts 22kW charging—this combination is uncommon in UK homes.
You drive exceptionally high mileage—200+ miles most days, requiring very rapid turnaround charging.
You operate a fleet from home—if you’re running multiple vehicles for business and need to charge several in quick succession.
You have a specific vehicle like a Renault Zoe that can charge at 22kW and you regularly need that speed.
Cost isn’t a concern—22kW installations are significantly more expensive (often £1,500-£2,500+) and you’ll rarely use the full capability.
For typical domestic use, even high-mileage drivers, 22kW is overkill. The extra cost is rarely justified by the practical benefits.
The Cost Differences
Understanding the price implications helps inform your decision:
7kW installation (single-phase):
- Charger unit: £500-£900
- Installation: £300-£600
- Total: £800-£1,500
11kW installation (requires three-phase):
- Charger unit: £700-£1,200
- Installation: £400-£800
- Total: £1,100-£2,000
- If you need to upgrade to three-phase: add £2,000-£5,000+
22kW installation (requires three-phase):
- Charger unit: £900-£1,500
- Installation: £500-£1,000
- Total: £1,400-£2,500
- If you need to upgrade to three-phase: add £2,000-£5,000+
The cost difference between 7kW and 11kW isn’t enormous if you already have three-phase power, but upgrading your supply purely for faster charging rarely makes economic sense for residential users.
Real-World Example Scenarios
Scenario 1: Commuter with 40-mile daily round trip
- Battery use per day: ~13kWh
- Charging time at 7kW: ~2 hours
- Overnight charging window: 10 hours
- Recommendation: 7kW is perfect. You’re using less than 20% of available charging time.
Scenario 2: Sales representative driving 120 miles most days
- Battery use per day: ~35kWh
- Charging time at 7kW: ~5 hours
- Charging time at 11kW: ~3.2 hours
- Overnight charging window: 8 hours
- Recommendation: 7kW works, but 11kW offers more flexibility if you have three-phase power.
Scenario 3: Uber/taxi driver doing 200+ miles per day
- Battery use per day: ~60kWh
- Charging time at 7kW: ~8.5 hours
- Charging time at 11kW: ~5.5 hours
- Need to charge quickly during break periods
- Recommendation: 11kW minimum, potentially 22kW if your car supports it. However, at these mileage levels, public rapid charging during breaks is probably also necessary.
Scenario 4: Two-EV household, both cars parked overnight
- Combined daily use: ~25kWh
- Charging time at 7kW (alternating): ~4 hours total
- Overnight window: 12 hours
- Recommendation: Single 7kW charger works, or consider two 7kW chargers rather than one faster unit.
What About Future-Proofing?
Some people consider installing faster charging capability “just in case” they need it in the future. This logic has some merit, but consider:
Your supply limitation is fixed—if you have single-phase power now, installing an 11kW charger won’t help until you upgrade your electrical supply (expensive and disruptive).
Your next EV might not charge faster—many mainstream EVs will continue to support 7kW or 11kW maximum. Not every vehicle is moving to 22kW AC charging.
Rapid DC charging is improving—public charging infrastructure is advancing rapidly. By the time your home charger needs replacing (10+ years), the charging landscape will be completely different.
Installation costs can be updated later—if you genuinely need faster charging in five years, you can upgrade then. The installation cost then will likely be lower than paying a premium now for capability you don’t use.
Future-proofing makes sense for technology that’s hard to upgrade later. Home chargers are relatively easy to replace when needed, so paying significantly more now for unused capability has limited justification.
The Bottom Line
For most UK homeowners, a 7kW charger is the right choice. It handles typical driving patterns comfortably, costs less to purchase and install, and works with standard single-phase electricity supply that virtually all homes have.
Consider 11kW if you already have three-phase power, your car supports it, and you regularly drive 100+ miles per day with limited overnight charging time.
22kW is rarely justified for residential installations—it’s expensive, requires three-phase power, few cars support it, and most people simply don’t need the speed.
Rather than choosing based on “more is better” logic, calculate your actual requirements based on your driving patterns and available charging time. In most cases, you’ll find that 7kW provides everything you need with time to spare, allowing you to save money on both the charger and installation while still enjoying the full convenience of home charging.
Not sure which charging speed is right for your driving patterns? Local EV’s certified installers will assess your electrical supply, discuss your daily mileage and routine, and recommend the most cost-effective solution for your genuine needs. We’ll help you avoid overpaying for capability you won’t use, while ensuring your charger can handle your actual charging requirements. Get in touch today for expert advice and a free quote.