The cheapest three hours of the day to run your washing machine could save you £63 a year, roughly the cost of a week’s food shop. That figure comes from analysis by energy consultancy Eco Experts, as reported by Cheshire Live, which looked at time-of-use tariffs available to households with smart meters.
Who qualifies, and who doesn’t
Time-of-use tariffs, such as Octopus Energy’s Agile or EDF’s GoElectric, offer lower rates during off-peak periods, typically between 10pm and 8am, or 1pm and 4pm in summer. To access them, you need a smart meter that records half-hourly consumption. Ofgem says 32 million smart meters are now installed across Great Britain, but not all households are on a time-of-use plan. You must actively switch to one. The catch: these tariffs often have higher daytime rates, so they only work if you shift at least 30% of your electricity use to the cheap window. The Energy Saving Trust recommends a minimum 40% shift to break even.
What it costs a typical 3-bed semi
A typical 3-bed semi using 2,900 kWh of electricity per year on a standard variable tariff pays about 28p per kWh. On a time-of-use plan, the off-peak rate might drop to 12p per kWh while the peak rate rises to 35p. If you run your washing machine (0.8 kWh per cycle) three times a week during off-peak hours, you save about £1.20 per week, £63 a year. Add a tumble dryer or dishwasher, and the saving climbs toward £100. But the numbers assume you have a smart meter and actually shift usage. Officials have not confirmed when all suppliers will offer these tariffs, though Octopus and EDF already do.
How this affects your EPC
Your Energy Performance Certificate doesn’t directly credit time-of-use tariffs, but it does measure estimated energy costs. A lower annual bill from load-shifting can improve the cost metric on your EPC, potentially nudging you from band D to C. More importantly, pairing a time-of-use tariff with solar panels or a home battery can cut grid electricity use by 60–80%. The government’s Boiler Upgrade Scheme doesn’t cover batteries, but the Smart Export Guarantee pays you for surplus solar power exported during peak hours, which aligns neatly with off-peak washing.
What this misses, and what to do next
But the advice to ‘wash at the cheapest three hours’ glosses over one thing: not everyone can shift their routine. Night workers, families with young children, or those in rented flats with shared laundry facilities may find it impossible. The real opportunity is for households with smart meters and flexible schedules. Ofgem’s data shows only 10% of households are on time-of-use tariffs, despite 90% having smart meters. The barrier is awareness, not technology. If you can shift your laundry to 11pm, do it. If you can’t, look at other measures: draught-proofing costs £50–£100 and saves £40 a year; a smart thermostat saves £75 on heating. Every pound counts when the price cap is rising again in October.
To check if a time-of-use tariff works for you, use the Energy Saving Trust’s online calculator. Compare your current unit rate with off-peak offers on comparison sites like Uswitch. Switch before winter, demand and prices peak between 4pm and 7pm, exactly when you don’t want to be running the machine.
Frequently Asked Questions
Yes, smart meters are essential because they measure half-hourly consumption, which suppliers use to bill at different rates. Over 30 million UK homes have one, but you must request a specific time-of-use tariff from your supplier. Octopus Energy's Agile tariff is a popular option, but check eligibility on their website.
It can, but the math changes. Solar panels generate most power during the day, so running the machine at midday uses free solar electricity. If you have a battery, you can store cheap off-peak grid power and use it later. In both cases, the saving from load-shifting is smaller than with grid-only use, but you still benefit from lower overall costs.
