Our Calculation Methodology & Data Standards
How EV Rate Check sources tariff rate sheets, models home charger installations, applies rebate caps, and updates cost estimates.
1. Tariff Data Sourcing & Verification Cadence
Unlike automated price comparison websites that rely on aggressive HTML scraping (which frequently breaks or misinterprets tiered structures), EV Rate Check uses a human-in-the-loop, primary-source verification model.
Primary Official Sourcing
Every unit rate, standing charge, and off-peak window is verified against published supplier standard variable or fixed rate tables (e.g. Octopus Energy, British Gas, EDF Energy, E.ON Next, OVO Energy, Scottish Power, PG&E, and the Ontario Energy Board).
Verification Cadence
Weekly: Top domestic EV tariffs (such as Octopus Intelligent Go, OVO Charge Anytime, and British Gas Electric Driver).
Monthly: Secondary domestic plans, regional DNO standing charge benchmarks, and municipal rebate programs.
2. EV Electricity Tariff Comparison Formula
Our rate comparison tool computes the estimated monthly cost of powering an electric vehicle based on your specific driving habits and home charging profile.
Mathematical Formula
1. Monthly kWh = (Annual Mileage / Vehicle Efficiency) / 12
2. Off-Peak Energy Cost = (Monthly kWh * Off-Peak Share %) * Off-Peak Rate
3. Peak/Day Energy Cost = (Monthly kWh * (1 - Off-Peak Share %)) * Peak Rate
4. Monthly Standing Charge = (Standing Charge / day) * (365 / 12)
Total Monthly Cost = Off-Peak Cost + Peak Cost + Standing Charge
Default Baseline Assumptions:
- Default Annual Driving Distance: 7,400 miles/year for the UK (UK Department for Transport national average) and 10,000 miles/year for the US/Canada.
- Default Vehicle Efficiency: 3.5 miles per kWh for the UK/Europe (typical for vehicles like the Tesla Model 3, MG4, and VW ID.3) and 3.0 miles per kWh for North America (reflecting larger crossovers and SUV battery packs).
- Off-Peak Charging Window Overlap: Defaulted to 90% off-peak. We assume an intelligent home charger or EV scheduling software automates charging during the lowest cost overnight window, with only 10% daytime top-ups. Users can adjust this slider from 50% to 100%.
- Standing Charge Normalization: Standing charges (quoted in pence per day or cents per day) are normalized to a monthly figure using the astronomical average of 30.42 days (365 days / 12 months).
3. Home EV Charger Installation Cost Model
Home charger installation costs consist of equipment, electrical labor, civil work/materials, and applicable government grants.
Baseline Range Derivation
Baseline figures reflect a standard 7kW (UK) or 40A Level 2 (US/Canada) installation with a modern electrical panel (≥100A UK, 200A US) and short cable run (≤10m / 25ft).
- UK Standard: £750 – £1,150
- US Standard: $950 – $1,650
- Canada Standard: CAD $1,100 – $1,900
Add-On Options & Complexity Multipliers
Each physical variable adjusts both the lower and upper bounds of the cost bracket:
- Cable Run: Medium (+£120/+$150); Long (>20m/50ft with trenching: +£350/+$450).
- Electrical Service: Panel upgrade or load management shedder (+£800 – £2,000 / $1,500 – $3,000).
- Hardware Power: Commercial 22kW (3-phase) or 48A hardwired (+£250/+$200).
4. Rebate Capping & Strict Statutory Exclusions
Rebates and tax incentives are subject to strict statutory rules. Our calculator enforces the following legal criteria:
- Total Cost Cap: Rebates cannot exceed the subtotal of the installation. The estimated net cost cannot drop below zero.
- Section 30C Expiration: The US Federal Alternative Fuel Vehicle Refueling Property Credit (IRC Section 30C) expired after June 30, 2026. Because today is September 29, 2026, Section 30C is completely excluded from active installation estimates and classified as an educational historical note.
- Federal EV Purchase Tax Credit Termination: US federal clean vehicle tax credits under the former Clean Vehicle Credit provisions were terminated on September 30, 2025 and are never included in our calculations.
Important Limitation Notice
Electricity rates vary significantly by region (distribution network operator / DNO zones in the UK; utility service territory in the US and Canada), meter type (SMETS2 vs. legacy meters), and payment method (monthly direct debit vs. payment on receipt of bill). Always obtain an official personalized quote from the electricity supplier before initiating a switch or tariff change.
How to Report Outdated Rates
If a utility provider has published a new rate card or if an incentive program has closed early, please alert our research desk. We verify and deploy updates within 24–48 hours.