An average washing machine uses around 1 kWh per 60-degree wash cycle. With an average cost of 17 pence per kWh and a laundry detergent cost of about 10 pence per wash, in combination with the cost of water, it equals to about 35 pence per load of laundry. There is money to be saved by doing the laundry during the night, but if you live in a flat, you should be aware that this can be disturbing for your neighbours.