If you charge an electric car at home, your electricity tariff can matter almost as much as the car’s efficiency. The difference between paying a standard day-rate and using a well-matched EV time-of-use (ToU) or smart charging tariff can easily run into hundreds of pounds per year — without changing your car.
This guide breaks down the main tariff types available in the UK, compares the best-known EV-focused options, and shows (with worked examples) how tariff choice and charging behaviour affect annual costs. It also explains how smart chargers and vehicle APIs can automate cost optimisation, so you get the cheap rates consistently rather than “in theory”.
1) The UK tariff landscape for EV charging: what actually matters
Ignore the marketing labels for a moment and focus on four variables that drive your EV charging cost:
- Your off-peak unit rate (p/kWh)
- The length and timing of the cheap window (e.g., 00:00–05:00 vs 00:00–06:00 vs 23:30–05:30)
- The day/peak rate (some EV tariffs “pay for” cheap nights with higher days)
- How reliably you can shift charging into the cheap periods (automation is key)
As a rule of thumb, EV tariffs are most attractive when:
- you can do most charging overnight, and
- your household can tolerate (or avoid) higher peak/day rates.
Industry summaries regularly cite off-peak EV rates in the high single digits p/kWh, versus mid-20s p/kWh for standard variable pricing, though the exact numbers vary by supplier, region, and time (The Electric Car Scheme).
2) The main tariff types, compared
A) Fixed off-peak “whole home” EV tariffs (the classic ToU model)
These tariffs give you a predictable low rate overnight for a set block of hours, and a higher rate outside that window. The cheap rate usually applies to your entire home, not just the car — so dishwashers, washing machines, immersion heaters and home batteries can also benefit.
Examples (illustrative supplier features and published windows/rates):
- Intelligent Octopus Go: six hours overnight for the whole home (11:30pm–5:30am) with very low advertised pricing, plus “smart charging” scheduling that may add extra cheap hours depending on grid conditions. (Octopus Energy)
- British Gas Electric Driver / EV tariff: off-peak window of 12am–5am, marketed at very low p/kWh overnight. (British Gas)
- E.ON Next Drive: off-peak window of 12am–6am, with fixed ToU positioning and smart meter requirements. (E.ON Next)
- ScottishPower EV Saver: off-peak window of midnight–5am with a published low p/kWh night rate. (scottishpower.co.uk)
- EDF GoElectric: positioned around overnight off-peak pricing for EV charging, with published examples using ~9p/kWh off-peak (regional pricing varies). (EDF)
Who it suits: Most home EV drivers who can charge predominantly overnight and want predictability.
Main risk: If the day rate is materially higher than your current tariff, and you have high daytime consumption (e.g., home working, electric cooking, heat pumps without load shifting), savings can shrink quickly.
B) Smart charging add-ons (cheap EV charging “any time”, but controlled)
Instead of giving your whole home a cheap off-peak window, some suppliers offer an EV-specific rate through smart charging integration. You plug in when you like, but the supplier (via app/API) controls when the car actually draws power.
A prominent model is OVO Charge Anytime, which is structured as an add-on plan with published EV charging rates and eligibility conditions (ovoenergy.com).
Who it suits: Drivers who cannot reliably keep charging within a fixed overnight window (shift workers, unpredictable schedules), but who are happy to let the supplier control charging.
Main risk: Compatibility and control. These products often depend on specific vehicle integrations or charger models, and may not optimise whole-home usage unless paired with separate automation.
C) Dynamic and half-hourly pricing tariffs (maximum opportunity, maximum volatility)
Dynamic tariffs track market conditions and update prices frequently (often half-hourly). The best-known UK example is Octopus Agile, where prices vary through the day and reward flexible consumption. (Octopus Energy)
Who it suits: Highly engaged users with automation (smart charger, home energy management, batteries) who can avoid peak pricing and actively chase low-cost periods.
Main risk: Price spikes at peak times. If you “have to charge” at 6pm, a dynamic tariff can be punishing. This is rarely the best choice without automation and discipline.
D) Solar + battery ToU tariffs (optimising import and export)
If you have solar PV and/or a home battery, your best tariff might be designed around import/export time bands, not just EV charging. For example, Octopus Flux is explicitly positioned as an import/export tariff with a peak band (typically 16:00–19:00) designed to encourage battery discharge/export at high-value times. (Octopus Energy)
Who it suits: Homes with solar/battery systems where value comes from both buying cheaply and exporting strategically.
Main risk: Complexity. You need to understand your household load profile, battery behaviour, and export rates — not just EV charging.
3) Case studies: how tariffs change annual charging costs
To make the maths tangible, let’s use two realistic UK driving profiles and compare “standard tariff charging” versus “good EV ToU charging”.
Assumptions (kept deliberately simple)
- Home charging share: 80% (the remainder is public charging or workplace)
- Vehicle efficiency: 3.5 miles/kWh (a reasonable blended figure for many EVs)
- Standard electricity unit rate: 28p/kWh (illustrative mid-20s benchmark) (The Electric Car Scheme)
- EV off-peak unit rate: 9p/kWh (illustrative, consistent with several suppliers’ published EV night-rate positioning) (British Gas)
Note: standing charges, regional rates, and day-rate uplifts are not included below. Use these examples to understand the direction and scale of savings; then validate against your own quotes.
Case study A: 8,000 miles per year (typical private driver)
- Annual kWh required = 8,000 ÷ 3.5 = 2,286 kWh
- Home-charged energy (80%) = 2,286 × 0.8 = 1,829 kWh
Cost on a standard tariff:
1,829 kWh × £0.28 = £512/year
Cost on an EV off-peak tariff (if all home charging is shifted off-peak):
1,829 kWh × £0.09 = £165/year
Indicative annual saving on home charging: ~£347/year
Even if you only manage to shift, say, 70% of your home charging into cheap hours (because of late returns, ad-hoc top-ups, etc.), the savings remain meaningful.
Case study B: 12,000 miles per year (high-mileage commuter)
- Annual kWh required = 12,000 ÷ 3.5 = 3,429 kWh
- Home-charged energy (80%) = 3,429 × 0.8 = 2,743 kWh
Cost on a standard tariff:
2,743 kWh × £0.28 = £768/year
Cost on an EV off-peak tariff (100% shifted):
2,743 kWh × £0.09 = £247/year
Indicative annual saving on home charging: ~£521/year
At higher mileage, tariff optimisation becomes a core part of running-cost management.
4) How smart chargers (and EV integrations) actually minimise costs
A ToU tariff only saves money if you consistently charge in the cheap window. That’s where smart charging features stop being “nice to have” and become financially material.
What “smart charging” should do in practice
A good setup will:
- Schedule charging to start/stop automatically within off-peak hours
- Hit a target state of charge by a departure time (not just “charge now”)
- Avoid peak pricing on ToU or dynamic tariffs
- Respect electrical limits (load balancing, max current, CT clamp integration if available)
- Provide reporting: how many kWh were charged off-peak vs peak
Tariff integration can go beyond simple timers. For instance, Intelligent Octopus Go explicitly combines an overnight off-peak block with smart charging that may schedule additional cheap periods (Octopus Energy). On dynamic tariffs such as Agile, price-aware automation is the difference between saving money and accidentally charging at the worst time (Octopus Energy).
Smart charger vs “car scheduling”: which is better?
- Car scheduling (built-in timers) can work for basic midnight-to-5am charging, but it is often crude: limited logic, no tariff awareness, and sometimes unreliable after app updates or connectivity issues.
- Smart charger scheduling using a charger such as the Humax MX7 is usually more robust and can integrate with household load, solar diversion, and multiple vehicles.
- Supplier-controlled smart charging (e.g., add-ons that manage charging through apps/APIs) can be excellent for “plug in any time” convenience, but you must be comfortable with external control and integration requirements (ovoenergy.com).
5) A practical decision framework: choosing the right tariff for your home
Use this checklist to shortlist the right tariff type before you compare quotes:
Step 1: Understand your charging pattern
- Do you typically plug in before midnight, and can you leave it plugged until 5–6am?
- Do you need frequent top-ups at unpredictable times?
- Do you have more than one EV sharing the charger?
If your charging is predictable: fixed ToU EV tariffs are usually simplest.
If unpredictable: consider smart charging add-ons or a tariff with a longer off-peak window.
Step 2: Estimate how much load you can shift off-peak
If you can shift 33%+ of household electricity into off-peak windows, ToU tariffs often look better (some suppliers explicitly flag this concept). (scottishpower.co.uk)
High shiftable loads include:
- EV charging
- home battery charging
- dishwashers / washing machines / tumble dryers (where appropriate)
- immersion heater schedules (if you understand the safety controls)
Step 3: Watch for the “day-rate penalty”
Two households with identical EV mileage can see very different outcomes depending on daytime consumption. If you have:
- lots of home working,
- electric cooking every evening, or
- an electrically-heated home with limited thermal storage,
…then the higher day rate on some EV tariffs can erode gains. In that scenario, a smart charging add-on (EV-only cheap rate) may outperform a whole-home ToU tariff — even if the headline off-peak window looks attractive.
Step 4: Ensure the metering and eligibility stack is in place
Many EV and ToU tariffs require:
- a smart meter, often with half-hourly readings enabled (supplier consent)
- app-based account management
- compatible EV/charger for smart features
E.ON Next Drive, for example, explicitly positions around smart metering and its off-peak window (E.ON Next). ScottishPower similarly frames EV Saver around smart metering and an overnight window (scottishpower.co.uk).
6) Cost optimisation beyond tariffs: small changes with outsized impact
Once you have a good tariff, focus on “behavioural automation”:
- Set a default charging target (e.g., 70–80% daily, 100% only for long trips). This reduces energy throughput and keeps charging within cheap windows.
- Use departure-based schedules, not start-time schedules. Your aim is “ready by 7am”, not “start at midnight”.
- Avoid peak-time top-ups unless necessary. On many tariffs, 4pm–7pm is structurally expensive (and on some products it is explicitly treated as peak). (Octopus Energy)
- If you have solar/battery, consider a tariff designed for import/export value, not just EV nights (Flux-style structures are built around this). (Octopus Energy)
The bottom line
For UK households charging at home, the “best” tariff is not simply the one with the lowest advertised p/kWh overnight. It is the tariff whose cheap periods you can consistently access — ideally through smart charger automation — and whose day/peak pricing doesn’t punish the rest of your household.
As a starting point:
- If you want simplicity and predictable savings: shortlist fixed EV ToU tariffs with 5–6+ cheap hours overnight. (British Gas)
- If you value flexibility and don’t always charge overnight: evaluate smart charging add-ons where the supplier optimises charging for you. (ovoenergy.com)
- If you have solar/battery or you enjoy optimisation: investigate import/export ToU or dynamic tariffs, but only with strong automation. (Octopus Energy)
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