Is Octopus Still the Best EV Tariff? Compare the Whole Bill
A cheap overnight EV tariff can look like an obvious winner. But the price of charging your car is only part of your electricity bill. Daytime rates, standing charges and the amount of energy you can move overnight all influence whether a tariff suits your home.
After looking at Intelligent Octopus Go Loyal in my previous video, I compared the wider competition. The useful question is whether staying with a supplier still makes financial sense for your particular household.
Why the overnight rate can mislead
The research covered suppliers including EDF, E.ON, British Gas, Good Energy, So Energy, 100Green and Utility Warehouse. I used six selected public offers with full regional prices for the numerical household comparisons.
In the recording’s Eastern-region snapshot, EDF’s eighteen-month GoElectric offer had a 6.66p overnight rate, compared with 7.60p for public Intelligent Octopus Go. So Energy’s overnight rate was 7.14p, but its daytime price was 42.88p. EDF’s eighteen-month daytime rate was about 32.70p.
Those figures show why the cheapest car charging does not necessarily produce the cheapest household bill. They are research-date examples, not a promise that these prices remain available. The EDF twelve-month offer also had different day and standing charges.
Compare the same house and car
My typical-home illustration uses 2,500 kWh of household electricity a year. The high-use case uses 25 kWh a day. Both exclude the car, which is added separately in every comparison.
The EV assumptions are 8,000 miles a year, four miles per battery kWh and 90% charging efficiency. That gives about 2,222 kWh a year at the meter. I assumed 30% of household electricity is used directly overnight, with the rest outside the cheap window. There is no solar generation or export income.
Without a battery, the typical-home annualised cost was about £958 on EDF’s eighteen-month offer and £1,070 on public Intelligent Octopus Go. These totals include standing charges and EV charging.
What a Powerwall changes
The battery illustration uses a 13.5 kWh Powerwall 2, a 10% backup reserve and 90% round-trip efficiency. That leaves up to 12.15 kWh a day available for household delivery under the simplified assumptions.
Adding it brought the typical-home totals closer: approximately £515 for EDF, £554 for So Energy and £562 for Intelligent Octopus Go. Small differences should not be treated as decisive when household habits and model assumptions can move them.
At 25 kWh of household use a day, the battery could not cover all outside-window demand. The illustration still required 5.35 kWh a day at the daytime rate. With the battery, EDF came to about £1,485 and Intelligent Octopus Go to £1,672.
These are electricity-bill comparisons for an already-owned battery. They exclude purchase cost and wear, and annualise the research-date prices, including the temporary VAT treatment. They are not guaranteed bills for the next year.
Eligibility and the cost of switching
Check whether an offer discounts the whole home or only eligible EV charging. An EV-only discount cannot be applied to your household or battery consumption. Equipment requirements and service bundles also need to be considered separately.
An exit fee changes the switching calculation too. If leaving costs £50 and another tariff saves £100 a year, the illustrative break-even point is six months. That is not an assertion about the loyalty offer’s exact fee.
EDF’s eighteen-month offer was lowest among the six public tariffs in all four illustrations. That does not establish a winner for every household or prove that it beats the account-specific loyalty quote. Compare that quote’s full terms before deciding.
Watch the full comparison: Is Octopus Still the Best EV Tariff? I Compared the Competition.
Which tariff are you using, and how much of your household electricity can you move overnight?
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