Running the dishwasher overnight only saves money if you are on a time-of-use electricity tariff, such as Economy 7, according to energy and appliance experts. For most households on standard single-rate tariffs, the cost is identical at 3am and 6pm, so shifting usage times brings no savings.
Energy bills rose by 4% for many households from October 1 after the price cap increased. Households paying by direct debit on a standard variable tariff now face an average annual bill of £1,723, or about £144 a month. These rates remain in place until December 2026.
Higher gas prices account for most of the increase, so households will feel the biggest impact when paying for heating and hot water this winter. Energy costs have reached a three-year high, with the ongoing Middle East conflict pushing up global wholesale gas prices and making the market less stable.
Electricity and gas price changes
Electricity unit prices have risen by less than 1% since October 1, while gas unit prices have increased by 8.7%. Ofgem reviews the cap every three months. It says the smaller rise in electricity prices is partly down to the Government temporarily removing VAT from electricity bills. The price cap does not limit total bills; it limits the rate suppliers can charge per unit of energy (kWh).
Gareth Kloet, an energy specialist at Go.Compare, said washing machines and dishwashers are among the household appliances that use the most electricity. Running them during cheaper, off-peak hours can save money, but only on a time-of-use or dual-rate tariff. If you pay the same rate all day, changing when you run them will not cut the cost.
He said: "Be sure to check the details of your tariff to find out what rate you're on and whether it includes different price bands throughout the day."
"If you are on a time-of-use tariff, off-peak times tend to be overnight, generally between 10pm and 8am. Some also include lower rates around mid-afternoon, so if you're often at home around this period, then this will probably be the best time for you to put on a wash and set the dishwasher away. If you're usually out during the day, putting them on overnight or first thing in the morning can also be a great way to save money on your energy costs. Just be mindful of your neighbours when doing so - if your appliances are close to their walls, then you might create a disturbance by putting them on too early or too late."
"The exact times of the lower rates can vary by supplier and tariff, so make sure you check the details of yours to find out exactly when they offer the cheapest prices, then you can plan your washing schedule around these."
Safety warning and expert advice
There is an important safety warning: fire services advise against running these appliances overnight or while you are out, as another expert explains below.
Simon Bones, founder and CEO of home retrofit company Genous, said some suppliers offer tariffs with electricity prices that change throughout the day. On these tariffs, running your washing machine, tumble dryer or dishwasher during cheaper hours can reduce costs. He added: "If you have a lot of electricity-hungry appliances, you could also consider a home battery. A battery can charge when electricity is cheaper and then power your home when prices are higher, meaning you can take advantage of cheaper electricity without having to change when you use your appliances."
"The downside is that home batteries can be expensive to install, and you'll need a qualified professional to fit one. However, you don't necessarily need solar panels or a heat pump to use a battery, although having them can make the savings more worthwhile."
"The important thing to remember is that time-of-use tariffs aren't automatically cheaper. If you use most of your electricity during the expensive periods, you could actually end up paying more. There are also significant differences between suppliers and tariffs, and not every supplier currently offers them."
"So, if you're considering switching to a time-of-use tariff this autumn, compare the tariffs carefully and think about when you actually use electricity. If you can shift some of your biggest electricity uses, such as washing, drying and cooking, to cheaper periods, that's where the potential savings are."
Practical tips for cutting appliance costs
Richard Howarth, laundry product manager at Hoover, Haier UK & Ireland, said there is no single best time to run appliances. It depends on your tariff. On a time-of-use tariff such as Economy 7, using them during off-peak hours costs less. He said the biggest savings come from how you use your appliances. For washing machines, choose a cooler wash of 20-30°C where possible, run full loads and use the eco programme. Heating water uses most of the energy in a wash cycle, so a lower temperature can reduce the cost.
Ana Padilla Martinez, e-commerce and marketing specialist at plumbing and heating supplier Plumb2u, agreed that timing makes no difference for most British households. She said: "If you are on a standard single rate tariff, and most people still are, a unit of electricity costs exactly the same at 3am as it does at 6pm. Running the dishwasher overnight saves nothing."
"It only saves money if you are on a time-of-use tariff, which means Economy 7, Economy 10 or one of the newer smart tariffs. On those, off-peak is usually overnight and the saving is real and worth having. So the first thing a reader should do is not reschedule their washing, it is check which tariff they are actually on. Rescheduling without checking is a lot of effort for nothing."
"I would add one caution, because it gets left out of these pieces. Fire services advise against running washing machines, dishwashers and tumble dryers overnight or when you are out of the house. If somebody does move to off-peak washing, a delay timer that finishes while they are awake is the sensible version."
Ana also recommended cooler washes and using the dishwasher's eco setting, which uses less water and energy. Keeping both machines in good condition can help too. Limescale on heating elements makes it harder to heat water, so the machine uses more electricity. Ana advised running a hot maintenance cycle with descaler every few months and using the right amount of detergent for your area's water hardness.
She also recommended keeping filters clean, as blockages can make machines work harder and waste energy. Check flexible water inlet hoses if they are more than five to 10 years old. This is less about saving energy and more about avoiding costly damage from a burst hose.
She concluded: "Full loads. Two half loads use close to twice the water and twice the heating of one full one. It is the least interesting tip on the list and it saves more than the clever ones."
