Why is electricity cheaper at night? Peak and off-peak electricity times explained

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With energy prices still much more expensive than they were before the cost of living crisis began, the ability to make any savings on your gas and electricity bill is crucial.

While there are some energy deals out there that could help you with your energy costs, the simplest way to slash your bills is by following our energy saving top tips. You may even be able to take advantage of tariffs that better suit your lifestyle.

Two forms of tariff that could be your ticket to lower bills are time of use and EV tariffs. Or, if you’ve got an economy 7 meter, you may also be able to keep your costs down by shifting when you use most of your energy. All three of these options make a distinction between peak times and off-peak electricity times, offering cheaper rates during quieter periods when demand for energy is less.

So, when do these hours fall – and how can you use them to your advantage? Here’s a quick guide.

What are peak and off-peak electricity times?

Put very simply, peak hours are times of the day when energy usage in the UK is at its highest. By contrast, off-peak times are periods when less energy is generally being used across the country. If your tariff is a time-dependent one, knowing when these different hours kick in and end is crucial if you’re to keep your energy bills as low as possible.

  • Economy 7: in daytime hours (more on when these fall below), households with these meters will pay a premium that’s usually well above the rates set out by the Ofgem energy price cap. But at night, they can get discounts of up to 50% on price cap rates. For more, see How does an economy 7 meter work?
  • Time of use and EV tariffs: people with these tariffs also get rewarded with cheaper rates for shifting their energy use away from peak hours. Unlike economy 7 meter tariffs, these products don’t necessarily bake in a daytime premium. But you may still find yourself paying more for your energy at peak times, particularly if your deal tracks half-hourly wholesale rates. You will need a smart meter to get these tariffs.
  • All other types of tariff: peak and off-peak hours tend not to matter with most other tariff types because you will pay a flat rate for your energy regardless of what time it is. But some schemes, such as the National Grid ESO’s Demand Flexibility Service and British Gas PeakSave, provide the opportunity for households to earn credit on their bills for shifting their energy use to off-peak times.

When are peak and off-peak times?

The times deemed to be peak and off-peak vary from provider to provider. But there are some times that are universally considered to be peak or off-peak.

The three hours between 4pm and 7pm are always peak times during weekdays, given this is when many people will be returning home from work or school, cooking their main meal and (in the colder months of the year) putting the heating on. Some suppliers class 7am until 9am as another peak, and all other times as off-peak. Or, they may say all daylight hours are peak times.

Meanwhile, weekends are always off-peak as factories and offices tend either to be closed or running at a lower capacity than during the week. The same goes for night time hours.

Homes with an economy 7 meter installed will get seven hours of cheaper rates (hence why it’s called an economy 7), which will usually fall at some point between the hours of 11pm and 8am. If you have what is known as a ‘complex’ meter, such as an economy 10, you may have access to longer off-peak periods. But peak hours will be in effect at all other times.

In some cases, time of use tariffs run off half-hourly wholesale prices, for example, the Octopus Agile tariff. It means the price you’ll pay will depend on what your supplier is paying for energy, with costs tending to be lower at off-peak times and higher during peak hours. But occasionally, wholesale costs may spike at unexpected times, so this kind of tariff will not necessarily adhere to usual peak or off-peak periods.

If you’re unsure about when your peak and off-peak times fall, contact your supplier. They may contact you about an upcoming cheaper rates period if you’re on a wholesale prices-tracking time of use tariff.

Does the Ofgem price cap cover peak and off-peak unit rates?

The Ofgem price cap covers anyone on standard variable or economy 7 tariffs. However, it doesn’t cover time of use tariffs, so they can be either a lot cheaper or more expensive depending on when you use energy and how much you use.

Ofgem assumes the average household with an economy 7 meter that pays via direct debit will use 3,900 kWh of electricity per year. Assuming 42% of the home’s energy use comes at night time (the national average, according to Ofgem), the energy regulator says households will pay £1,219  a year on average under current price cap rates (for 1 October to 31 December 2023).

While suppliers can set their day and night rates at whatever level they like, they have to meet a weighted average unit rate that’s calculated by Ofgem. The weighted average takes into account the proportion of energy a typical household uses on the day rate versus the night rate (58% in the day, 42% at night). Put simply, a provider cannot set their day rate at a level that exceeds the night rate by too great an amount.

How to save money through off-peak energy hours

If you have an economy 7 tariff, using at least 40% of your energy at night will mean you’re more likely than not to be saving compared to if you were sitting on the Ofgem energy price cap. Given the variance in time of use rates, it’s hard to say exactly how much you would need to use away from peak times to make it viable.

But in both instances, moving as much of your energy use as possible to late-night or early morning periods should help to save you money. Here are some quick tips for how to maximise your savings:

    • Run your energy hungry appliances at night: if you can run your washing machine, tumble dryer and dishwasher in off-peak hours, you will cut your energy bill significantly. However, the caveat with this tip is that none of these appliances should be on when you’re fast asleep due to the fire risk. So, make sure you set them to turn on when you’re awake or about to wake up to be on the safe side.
    • Got a storage heater? Make sure it’s set to come on at night: economy 7 meters were first installed in the 1960s and 70s when storage heaters became popular. The idea is that they would heat up at night during cheap rates and then heat your home in the day. If this is the set up you have in your home, make sure your heater is set to come on in your cheaper hours and then switch off before day rate hours kick in.
    • Buy energy efficient appliances: it’s practically impossible to cut your energy use to nil during peak hours as appliances like radiators and freezers need to be kept running to work properly. Purchasing energy efficient models could save you money. All appliances now come with an EU Energy Label grading from A to G. You should aim for A-ratings as these are the most energy efficient.
    • Charge up power banks and devices at night: if you have a power bank that can be used by one or more of your devices (eg, phones, laptops or tablets), be sure to charge it in off-peak hours. That way you can slash your charging costs.
    • Set clock change reminders (economy 7 only): when the clocks go back an hour on 29 October, make sure your economy 7 changes with them or that you’re aware when your new off-peak hours fall. Unsure about whether you can change your meter’s clock? Contact your supplier.
    • For more energy saving tips, visit the Look After My Bills guide to slashing your energy use.