It's a debate that has raged on for years, with many energy bill hacks promising to slash your monthly outgoings by changing the time of day that you wash your clothes or heat your home.

One commonly repeated nugget of wisdom is about when the cheapest time to run your washing machine is, with many people believing that it's cheaper if you use your washing machine in the afternoon, or overnight.

But according to energy giant British Gas, that's usually not the case, and the supplier has waded into the debate to settle it once and for all.

The firm, in its energy saving tips advice, explains exactly how and when running appliances at night is cheaper, and when it isn't, and it really depends on the type of tariff you have.

It says: "Most homes across the country pay a 'flat' or single rate for electricity. This means the cost is the same whatever time of day you're using it."

It's only if you have a time-of-use tariff that you can save money, the most popular of these being Economy 7, which powers night storage heaters.

It continues: "Some homes are on a tariff called Economy 7 - which does give you seven 'off peak' hours in the night when your electricity is cheaper."

The firm adds: "Peak electricity, or 'peak electricity hours' are the times of day or night when people use more electricity as they get ready for work or school and then return in the evening.

"Using electricity at night to charge your electric vehicle or run Economy 7 storage heaters, can be cheaper with time-of-use, or off-peak electricity rates and tariffs - particularly if you also shift energy-intensive tasks like doing the laundry or charging appliances to the cheaper off-peak electricity night rate times."

But if you don't have an Economy 7 tariff, or a smart meter based tariff which changes price depending on the time of day, then you won't save anything by running the washing machine 'off peak'.

This is backed by Martin Lewis. Replying to a question on Twitter, Martin previously outlined way back in a post on October 6, 2022, during the peak of the energy price crisis: "Most don't have time-of-use tariffs so there's no price difference.

"If you do, night's cheaper. Yet peak use is 4pm to 9pm so for UK's energy security, not then is better."

Martin added: "If [you have] UV solar panels, use appliances in daylight hours."