Running a washing machine or dishwasher at a specific time of day only cuts energy costs for households on a time-of-use tariff, such as Economy 7. For everyone else on a standard single-rate tariff, the time of use makes no difference to the bill.
The energy price cap rose by 4% on October 1, pushing the average annual bill for direct debit customers on a standard variable tariff to £1,723, or about £144 a month, with these rates in place until December 2026. Most of the increase comes from higher gas prices, so the biggest impact will be felt on heating and hot water bills during the colder months.
Energy costs are at a three-year high, largely because the ongoing conflict in the Middle East has pushed up global wholesale gas prices and made them unpredictable. Gas and electricity prices have not risen at the same rate: the price of a unit of electricity has risen by less than 1% since October 1, while the price of a unit of gas has increased by 8.7%.
Timing only matters on time-of-use tariffs
Ofgem, which reviews the cap every three months, says the smaller rise in electricity prices is partly due to the Government's temporary removal of VAT from electricity bills. The price cap does not limit total bills; it limits how much suppliers can charge per unit of energy (kWh).
Gareth Kloet, an energy specialist at Go.Compare, said washing machines and dishwashers are among the home's most energy-hungry appliances. Running them during cheaper, off-peak periods can cut costs, but only if you have a time-of-use or dual-rate electricity tariff. He advised checking the details of your tariff to find out what rate you're on and whether it includes different price bands throughout the day.
On time-of-use tariffs, off-peak times tend to be overnight, generally between 10pm and 8am. Some also include lower rates around mid-afternoon. The exact times vary by supplier and tariff, so customers should check the details of their own plan to find the cheapest periods.
Home batteries and other savings
Simon Bones, founder and CEO of home retrofit company Genous, said some suppliers offer time-of-use tariffs with electricity prices changing throughout the day. Customers on these tariffs can save by using washing machines, tumble dryers and dishwashers during cheaper periods. He suggested that those with many electricity-hungry appliances could consider a home battery, which charges when electricity is cheaper and powers the home when prices are higher. However, batteries can be expensive to install and require a qualified professional.
Bones warned that time-of-use tariffs aren't automatically cheaper. If most electricity is used during expensive periods, customers could end up paying more. He advised comparing tariffs carefully and thinking about when electricity is actually used, noting that shifting big uses such as washing, drying and cooking to cheaper periods is where the potential savings lie.
Tariff check before rescheduling
Richard Howarth, laundry product manager at Hoover, Haier UK & Ireland, said there is no single best time to run appliances; it depends on the tariff. He said the biggest savings come from how appliances are used: for washing machines, use lower temperatures of 20-30°C where suitable, wash full loads and choose the eco programme, since heating water uses the most energy during a wash.
Ana Padilla Martinez, e-commerce and marketing specialist at UK plumbing and heating supplier Plumb2u, agreed that the time of day makes no difference for most British households. She said that on a standard single rate tariff, a unit of electricity costs the same at 3am as at 6pm, so running the dishwasher overnight saves nothing. It only saves money on time-of-use tariffs such as Economy 7, Economy 10 or newer smart tariffs, where off-peak is usually overnight. She advised checking which tariff you are on before rescheduling washing.
Padilla Martinez also cautioned that fire services advise against running washing machines, dishwashers and tumble dryers overnight or when out of the house. If moving to off-peak washing, a delay timer that finishes while people are awake is the sensible version.
She suggested washing clothes at cooler temperatures and using the dishwasher's eco setting, which uses less water and energy. Cleaning both appliances regularly can help cut costs: limescale can build up on heating parts, making them use more electricity to heat water. Running a hot maintenance cycle with descaler every few months and using the right amount of detergent for the area's water hardness can prevent this. She also advised cleaning appliance filters, as blocked filters make machines work harder, and checking flexible inlet hoses older than five to 10 years to prevent costly damage from a burst hose. She emphasised full loads, noting that two half loads use close to twice the water and twice the heating of one full one.
