People across the country are being advised to put their washing machines on at night because it will 'cost them less'. The theory goes that your electricity is cheaper at night than it is in the day.
Unfortunately, for the vast majority of people, this just isn't the case. Most homes across the country pay a 'flat' rate for electricity - meaning the cost is the same whatever time of day you use it.
A few homes are still on a tariff called Economy 7 - a system which does give you seven 'off peak' hours in the day when your electricity is cheaper. Unfortunately most energy companies don't offer this to most new customers, so usually only those with legacy meters still have access.