British Gas is to offer more than two million smart meter customers free electricity for eight-hour periods at weekends.
From this weekend, it is launching a new plan called FreeTime which gives smart meter customers free electricity between 9am and 5pm on Saturday or Sunday.
Customers will be able to choose which day of the weekend they would prefer to have the free electricity, when they will be able to mow the lawn or catch up on box sets without this adding to their energy costs.
British Gas has installed over 2.4 million smart meters in homes which provide meter readings directly to suppliers, meaning an end to estimated bills.
Dual fuel customers with British Gas smart meters already installed will be able to take up the deal, as well as anyone else who wants a smart meter and is able to have one installed. The average dual fuel bill will be £1,001, based on Ofgem average consumption.
British Gas said it has already been trialling the plans with thousands of customers, many of whom reported changing their behaviour, saving an average of £60 from their annual bill by shifting their energy use. Some 86% of customers said they believed the changes they made had reduced their spend.
It said the FreeTime deal will be fixed until March 2018 and will be the cheapest dual fuel deal currently offered by British Gas.
Sarwjit Sambhi, managing director of UK Home at British Gas said: "FreeTime is an industry first."
He added: "This will be the first of many smart meter innovations from British Gas."