Time-of-Use tariffs, and So Unique

With smart meters becoming the new normal, smarter electricity tariffs are being introduced. These tariffs consider not just how much energy we use, but also when we use it. They help households make cheaper, greener energy choices, save money, and support a sustainable energy system.

Let’s take a look at how it all works.

What is a Time-of-Use (ToU) Tariff? 

A Time-of-Use (ToU) tariff is a smart energy pricing plan where the cost of energy depends on when you use it, not just how much you use.

Instead of paying a flat rate all day, ToU tariffs charge different prices at different times. For example:

• Peak hours (usually mornings and evenings) cost more because a lot of people are using electricity at the same time.
• Off-peak hours (like overnight) are cheaper because fewer people are using electricity.

It’s a bit like peak and off-peak train times. You always pay more at peak times because a lot of people are using the trains. Off-peak travel is cheaper because fewer people are using them.

The great thing about Time-of-Use tariffs is you can save money by shifting some of your energy use to off-peak times. Like using the delay timer to run your dishwasher at midnight, or scheduling your electric car to charge overnight.

Pro Tip: You need a smart meter set to half-hourly readings to get a Time-of-Use tariff.

When are peak and off-peak energy times? 

Peak energy times are when electricity demand is highest, typically between 7am and 9am, and 4pm to 7pm on weekdays. This is when people are generally getting up and ready for work, or returning home and getting dinner ready. During these hours, electricity is more expensive because the grid is under more pressure.

Off-peak times are quieter periods when fewer people are using electricity. These are typically overnight (from around midnight to 5am), and on weekends. Many energy suppliers offer cheaper rates during these hours, especially on smart Time-of-Use tariffs.

Benefits of using energy in off-peak times

Using energy during off-peak times isn’t just good for your wallet, it’s also better for the planet. Plus, it helps to keep the electricity grid running smoothly. Here are the key benefits:

Potential cost savings

Customers on Time-of-Use (ToU) tariffs can save by shifting energy use into cheaper off-peak hours.

EV drivers, for example, can charge overnight for cheaper rates. Our So EV tariff offers a 6.5p per kWh to charge between midnight and 5am.

Load balancing 

Moving your energy use from peak times to off-peak times reduces pressure on the grid, making it more stable and efficient.

Environmental impact 

Using electricity during peak hours is less sustainable, because electricity demand is high, and the grid often relies on fossil fuel power stations to keep up. During off-peak times, renewable sources like wind and solar can meet the nation’s demand, making it a cleaner, greener time to use electricity.

Why a one-size-fits-all Time-of-Use (ToU) tariff might not work for you

Standard TOU tariffs offer cheaper electricity during off-peak hours, usually overnight or during the day when demand is low. But they’re not always the best fit for customers whose daily routine doesn’t allow for savings in the standard off-peak hours.

So Unique: our smarter, personalised Time-of-Use (ToU) Tariff

At So Energy, we appreciate that everyone’s different and has their own ways of using energy – and that’s a good thing. After all, our differences are what make us human. That’s why So Unique is designed around you – your home, your habits, and how you live. Because personalised energy isn’t just smarter, it’s fairer.

So Unique uses intelligent tech to create a personalised energy tariff based on how you use energy.

By analysing your smart meter data, we create your unique, personalised rates  – Peak, Off-peak and Super Off-peak. Simply by switching to the multi-rate So Unique tariff, you can save money compared to our So Flex standard variable tariff.

And, by shifting 20% of your energy use to your Off-peak or Super Off-peak hours, you can save up to £200 a year*. When you consider 14% of a typical home’s energy use is used for washing and drying clothes, and dishwashing, it’s not too hard to make savings**.

Real-world examples of how So Unique can benefit you 

Washing overnight

Most modern dishwashers and washing machines have delay timers, which make it easy to shift your high-energy tasks into off-peak hours.

Weekend cooking

Using slow cookers or scheduling ovens to run during off-peak hours can help reduce costs. For example, batch cooking at weekend, instead of peak evening hours can lower your electricity bill.

Home office charging

Charging laptops, monitors, printers, phones and other devices during off-peak hours can help you to save. Get a smart plug so you can schedule your devices to charge at cheaper times, then use their battery power during peak hours.

Other ways to save money on energy

As well as off-peak energy use, there are several other smart ways to cut your energy bills and make your home more energy-efficient.

Smart Meter

It all starts with a smart meter. This nifty bit of kit is the gateway to smart tariffs. But just by looking at your In-home Display, you can spot where you’re wasting energy, and make changes.

Smart home technology

Smart thermostats, plugs, lights, and other appliances let you automate and schedule energy use during cheaper times. They help you stay efficient without changing your routine.

Energy efficiency

Simple things like turning off stand-by mode, washing your clothes at 30 degrees, and taking shorter showers are all easy things to do to save on bills.

Footnotes

*The £200 saving claim is based on over 200 trial samples modelled against our So Flex Standard Variable Rate on 29 September 2025. Your actual savings will depend on how much energy you shift, and whether you shift to Off-peak or Super Off-peak times.

** https://energysavingtrust.org.uk/top-five-energy-consuming-home-appliances/

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