Do EV owners charge at peak times?

The practical picture is that most charging happens at home, and the timing of it is set by the tariff and the charger rather than by the driver standing at a plug. Three quarters of drivers surveyed in Scotland charge mostly at home, generally using a charging point attached to the house⁴. Home charging is simply cheaper and more convenient, especially where an energy provider offers cheaper electricity in off-peak periods such as late evening, overnight or early morning⁵.

What follows is when peak hours fall, how they differ between tariffs, how a smart charger moves load into the cheaper window, what that is worth, and what the Smart Charge Points Regulations actually require. The short version: off-peak charging is encouraged by regulation and rewarded by tariffs, but it is not compulsory, and the default settings on a new charger can be changed.

When peak hours fall, and why they cost more

Peak hours are the periods when electricity is dearest, and they cluster in the early evening. One supplier describes peak times as early evenings between 4pm and 7pm, when electricity tends to be more expensive⁶. Independent guidance on time-of-use tariffs puts the peak at typically 4pm to 7pm, and warns that a household may not save money if it cannot shift its use away from those times¹¹. Some heat pump tariffs carry a pricier peak rate between 4pm and 7pm as well¹².

The cost gap is the point. Boost charging during peak hours, such as 4pm to 7pm, can cost significantly more than using the overnight window¹³. That is the same logic that has always applied to Economy 7, where electricity outside the night window is charged at a more expensive peak rate¹⁴.

There is a second, regulatory definition of peak that does not match the tariff one. The Smart Charge Points Regulations describe times of peak electricity demand as between 8am and 11am, and 4pm and 10pm on weekdays⁷. That is the window a new charger is pre-set to avoid, and it is wider than the 4pm to 7pm that most suppliers price as peak. A household reading its charger's default schedule and its tariff's peak rate will therefore see two different sets of hours, and both are correct for their own purpose.

Research on real homes adds a third wrinkle. In Living Lab homes, peak charging occurred between midnight and 6am, consistent with behaviour optimising for current time-of-use tariffs¹⁵. In other words, what looks like a peak to the network and what looks like a peak to a tariff are not the same thing, and a household's charging can sit in a cheap tariff window while still landing in a period the network regards as busy.

Off-peak windows: midnight to 5am, 11pm to 6am and other definitions

There is no single national off-peak window. Typical supplier off-peak periods in the UK include 11pm to 8am, midnight to 7am and midnight to 5am⁸. One supplier's EV Charge tariff runs its off-peak window from midnight to 5am¹⁶. Another source describes EV tariffs as commonly offering off-peak from midnight to 5am⁹. Time-of-use periods are often late evening, overnight and early morning¹⁷.

Economy 7, the long-standing dual-rate tariff, uses a seven-hour window at night, typically midnight to 7am, with times that may vary between suppliers¹⁸. One description of the tariff gives night-time hours of 22:00 to 08:30¹⁹. The variation matters: a household that assumes a midnight start may find its own supplier begins earlier or later.

The practical consequence is that the length of the cheap window, not just its start time, determines how much of a car's charging can be done off-peak. A five-hour window, such as midnight to 5am, is a different proposition from an eight-hour one running from 11pm to 8am, and the difference shows up on the bill rather than on the dashboard¹.

How smart chargers shift charging into the off-peak window

A smart charger does the timing so the driver does not have to. One maker's smart charger automatically aims to charge the vehicle during the cheaper off-peak periods on a dual-rate tariff²⁰. The same product allows the owner to schedule charging during off-peak periods, optimise charging around the energy tariff, connect compatible EVs directly, monitor charging sessions and history, earn rewards and manage the charger remotely²⁰.

Smart chargers also handle solar. They can monitor real-time solar electricity production and adjust charging speed accordingly, drawing more or less power and switching between solar and grid supply depending on what is available²¹. That is a different kind of optimisation from tariff-shifting, and the two can pull in opposite directions on a sunny afternoon.

Charging apps commonly expose the setting directly. One app offers an only charge off peak option²². The charger, not the driver, then decides when the session runs within the window.

For a household, this is where energy independence is partly real and partly borrowed. The charger can move consumption into a cheaper window and can absorb surplus solar, which reduces reliance on the grid at expensive times. It cannot remove the dependence on the grid, the supplier or the tariff, and the scheduling logic usually sits in a manufacturer's app or cloud service rather than in the home.

What off-peak charging saves: hundreds of pounds a year

The published savings vary widely with tariff, mileage and the size of the gap between peak and off-peak rates. One supplier states that customers who arrange electric vehicle charging during off-peak times can save more than £700 per year⁹. Government guidance puts the figure for an average-consumption household with an EV at around £330 annually by smart-charging on a time-of-use tariff when compared with a static one¹⁰. An independent body describes smart EV charging as saving a typical EV driver hundreds of pounds a year²³.

At the level of a single charge, an off-peak tariff can bring a full charge in at less than £10²⁴. Independent guidance notes that some energy providers offer smart charging tariffs that make it cheaper to use electricity at night, or at times of low electricity demand²⁵, and that EV tariffs typically charge a cheaper rate for electricity used at night²⁶. One source describes the overnight rate as often the best option²⁷.

The spread between these figures is not a contradiction so much as a difference in assumptions. The £700 figure is a supplier's own claim for its customers; the £330 figure is a government estimate for an average-consumption household against a static tariff; the hundreds of pounds is a general description. A household's own saving depends on how many miles it covers, the car's efficiency, and the size of the peak-to-off-peak gap on its particular tariff.

The Smart Charge Points Regulations: encouraged, not mandatory

The law regulates the charger, not the driver. The Electric Vehicles (Smart Charge Points) Regulations 2021 require that domestic EV chargers must be smart, capable of responding to signals to shift charging to off-peak periods²⁸. All new domestic and business charge points must include smart functionality to support off-peak, lower-cost charging²⁹. One guide states the position bluntly: this is a legal requirement, not optional²⁸.

The detail is in the defaults. A charge point must incorporate default charging hours and must allow the owner to accept, remove or change these upon first use and subsequently⁷. The default hours must be pre-set to not charge during times of peak electricity demand, between 8am and 11am and 4pm and 10pm on weekdays⁷. To protect consumers from lock-in, a charge point must retain its smart functionality even if the owner switches electricity supplier⁷.

The regulations do not apply to sales of charge points before 30 June 2022⁷. Older units therefore sit outside the regime, and a household with an early charger may find it has no default schedule and no obligation to avoid peak hours.

What the regulations do not do is compel a household to charge off-peak. The owner can change or remove the default hours, and nothing in the rules requires a car to be plugged in during the cheap window. Off-peak charging is encouraged by the default setting and rewarded by the tariff, and that combination is what moves most charging into the night.

Vehicle-to-grid and the peak

Vehicle-to-grid technology takes the timing question further. It allows an EV charger to not only charge a vehicle but also take energy from it³⁰. More fully, it allows electric vehicles to draw power from the grid to charge their batteries and to send electricity back to the grid when needed, generating cash for the EV owner³¹. Because that export can be aimed at the times of highest demand, it helps reduce peak demand on the electricity network³².

For a household, V2G turns the car from a load that must be kept out of peak hours into an asset that can be paid for discharging during them. It does not remove dependence on the grid or the supplier; it changes the direction of flow at the margin. The technology is distinct from smart charging, which only shifts consumption rather than exporting it.

Where the evidence disagrees

Two figures on behaviour do not sit easily together. One maker states that the majority of EV owners charge when electricity is most expensive¹. Ofgem reports that off-peak EV charging appears to be common practice among many EV users, with room to grow further². A Zapmap survey puts 80% of EV owners on off-peak, renewable electricity tariffs for home charging³.

A tariff choice is not the same as a charging time, and a survey of tariff holders is not the same as a measurement of when cars are plugged in. Consumer Council research found that almost three quarters (73%) of EV and plug-in hybrid owners would be likely to charge their vehicle outside 4pm to 8pm if it meant a reduction in the cost, down from 81% in 2022³³. That is stated intention rather than observed behaviour, and the fall between the two years suggests the picture is not static.