How To Calculate The True Cost Of Charging Your EV At Home

For many EV owners, charging at home seems simple; plug in, wait, and drive off. But the cost of EV charging is influenced by several factors, including electricity tariffs, your vehicle’s battery capacity, charging habits, and even the time of day you charge. Understanding the actual cost helps you plan efficiently, avoid surprises on your energy bills, and maximise the benefits of switching to electric. 

At EVC Electrical Installations, we specialise in professional EV charger installations across Kent, London, and the South East. Our team can guide you in choosing the most cost-effective and suitable home charging solution. Contact us today for advice or to arrange an installation. Call us now on 01322 761101 or email office@evcinstalls.co.uk. 

Factors That Influence The Cost Of EV Charging At Home 

Charging your electric vehicle at home isn’t just about plugging in your car and switching it on. Several practical factors directly influence EV charging costs, and understanding them helps you plan your energy use effectively. Here’s what every homeowner should consider: 

 

1. Electricity Tariffs And Time-Of-Use Rates
   

   The price you pay for electricity varies depending on your tariff. Standard tariffs charge a flat rate, while time-of-use plans, often called “economy” or “off-peak” rates, cost less overnight. Charging during these off-peak hours can significantly reduce your monthly EV energy expenses. 

 

2. Battery Size And Vehicle Efficiency
   

   Larger batteries store more energy, which can increase charging costs if fully recharged frequently. Additionally, an electric car’s efficiency, how many miles it travels per kWh affects how much energy you’ll use over time. More efficient vehicles lower your per-mile charging cost. 

 

3. Charging Speed And Charger Type
   

   Home chargers come in different kW ratings. Higher-rated chargers (e.g., 7kW vs 3.6kW) can charge your car faster but may slightly increase energy costs due to higher power draw. Choosing the correct charger for your home and daily driving routine ensures cost-effectiveness without compromising convenience. 

 

4. Daily Mileage And Usage Patterns
   

   How far you drive each day determines how often you need to recharge. Frequent short trips may require multiple partial charges, while longer, less frequent journeys may allow for a single full charge. Understanding your driving habits helps in estimating a realistic monthly cost of EV charging. 

 

5. Renewable EnergyAndHome Integration
   

   If you have solar panels or a home battery system, you can offset some of the electricity costs. Using solar-generated energy to charge your EV reduces reliance on the grid, lowering overall energy expenses and improving sustainability. 

 

6. Charging EfficiencyAndEnergy Losses
   

   When you charge your EV, a small portion of the energy naturally turns into heat instead of being stored in the battery. Most home chargers have a small energy loss (typically 5–10%), which should be factored into your calculations to understand the true cost of each charge. 

For those just starting, consider starting with a beginner’s guide to charging an electric vehicle at home and in public. Even if public charging stations are available, most owners rely heavily on home charging for convenience and cost efficiency.   

 

How To Calculate Your Home EV Charging Costs Accurately 

Multiple variables affect the final cost, including electricity prices, battery capacity, and charger efficiency. Here’s a detailed step-by-step guide to calculate your true home charging costs. 

 

1. Know YourVehicle’sBattery Capacity
   

   Battery size is measured in kilowatt-hours (kWh), which tells you how much energy it can store. For example: 

• Small EVs: 30–40 kWh 

• Mid-range EVs: 50–60 kWh 

• Large EVs: 70–100 kWh 

A fully depleted 60 kWh battery will need 60 kWh of electricity to recharge (ignoring minor losses). This serves as the basis for calculating your charging costs. 

 

2. Determine Your Electricity Rate
   

   Electricity costs vary depending on your tariff:

• Standard rate: ~34p per kWh 

• Economy 7/off-peak rate: ~16–18p per kWh 

Using off-peak tariffs can halve your charging costs if you schedule overnight charging. 

 

3. Factor In Charging Efficiency

   
   Not all electricity supplied to yourcar’s battery is stored. Most home chargers have an efficiency of 90–95%, meaning 5–10% is lost during charging. For example: 

• Charging a 60 kWh battery at 90% efficiency requires ~66.7 kWh of electricity (60 ÷ 0.9). 

This slightly increases the total cost compared to a simple per-kWh calculation. 

 

4. Calculate The Cost Per Full Charge

   
   Once you know your battery size, electricity rate, and efficiency, calculating the cost is straightforward:

Cost per full charge = Battery capacity ÷ Charging efficiency × Electricity rate 

Example: 60 kWh battery, 90% efficiency, standard rate 34p/kWh: 

• 60 ÷ 0.9 = 66.7 kWh used 

• 66.7 × £0.34 ≈ £22.70 per full charge 

This gives a realistic estimate of the cost of fully charging your EV at home. 

 

5. Estimate Monthly Charging Costs

   
   Next, consider how often you charge based on your mileage:

• Average UK driver: ~25 miles per day (~750 miles per month) 

• Mid-size EV efficiency: ~4 miles per kWh 

Monthly energy consumption = 750 ÷ 4 = 187.5 kWh 

Using the same electricity rate (34p/kWh) and factoring efficiency (90%): 

• Adjusted kWh needed: 187.5 ÷ 0.9 ≈ 208.3 kWh 

• Total monthly cost: 208.3 × £0.34 ≈ £70.80 

This calculation helps homeowners budget realistically for EV charging. 

 

6. Consider Different Tariffs And Smart Charging

   
   Smart chargers allow you to schedule charging during off-peak hours. Switching to an economy 7 tariff (~16p/kWh) could reduce the monthly cost in the example above to:

• 208.3 × £0.16 ≈ £33.33 

Using smart apps and load management features can optimise both costs and energy use, especially if multiple vehicles are charged at the same property. 

 

7. Account For Home Energy Sources

   
   If your home has solar panels or battery storage, you can offset part of your energy use:

• Charging during the day with solar can reduce grid dependency 

• Example: If solar provides 50 kWh per month, the monthly grid cost reduces: 

• 208.3 − 50 = 158.3 kWh 

• 158.3 × £0.34 ≈ £53.80 

Integrating renewable energy can significantly reduce your overall EV charging costs. 

 

8. Plan For Long-Term Savings And Maintenance

   
   While upfront installation of a dedicated home charger adds cost (~£1,000–£1,200), it increases efficiency, reduces energy waste, and often qualifies for government grants like OZEV. Over time, the improved efficiency and smart charging features pay back the investment through lower monthly electricity costs.

 

Effective Ways To Reduce Your Home EV Charging Costs 

Understanding your EV charging costs is only the first step. Here are key strategies to keep your energy bills in check while charging at home: 

• Use Off-Peak Tariffs: Charge overnight with Economy 7 or similar plans to cut electricity costs by up to 50%. 

• Leverage Smart Chargers: Smart apps allow scheduled charging, load management, and energy monitoring, reducing wasted power. 

• Install a Dedicated Home Charger: A 7kW charger is more efficient and faster than a standard socket, and many OZEV grants cover part of the installation. 

• Integrate Solar Or Battery Storage: Use solar energy to charge during the day or store surplus energy for overnight charging, lowering grid dependency. 

• Optimise Driving Habits: Plan routes, avoid heavy acceleration, and charge only when needed to reduce energy use. 

• Consider Load Management For Multiple EVs: Efficiently distribute power across several vehicles to prevent peak-time spikes and wasted energy. 

• Track Usage And Incentives: Regularly review bills and charger data. Take advantage of grants and local incentives to reduce both installation and running costs. 

Conclusion 

Accurately understanding the cost of EV charging at home helps you plan better, save on electricity, and make the most of your electric vehicle. By considering factors like electricity tariffs, charger efficiency, energy usage, and smart charging strategies, you can get a clear picture of your true running costs. 

At EVC Electrical Installations, we make this process straightforward. From recommending the right charger to providing a seamless installation, we ensure your EV charging setup is efficient, safe, and tailored to your needs. Whether it’s a domestic 7kW home charger or a commercial solution for multiple vehicles, our team brings over 40 years of combined electrical expertise to every project.  

Contact us today on 01322 761101 or email office@evcinstalls.co.uk to arrange your installation and explore the options best suited for your home or business.