Families could save a collective £600 million a year in energy costs by switching gadgets off, a charity has calculated.
More than three-quarters of people admit to regularly leaving at least two devices on standby and 53% admit to leaving the TV on in a room when they are not watching.
The number of people with advanced set-top boxes has gone up by 52% since 2010, and leaving one on standby for 20 hours a day could cost around £20 a year, the Energy Saving Trust said.
of people regularly leave at least two devices on standby
Almost half of those who leave their TV on standby do so because it is more convenient and 22% say it is because they cannot access the plug or see no reason to turn it off.
A fifth of people regularly leave multiple televisions switched on in order to not to miss anything when moving between rooms.
Almost a third of people blame their spouse for leaving appliances switched on around the house and almost half blame their children.
Big Energy Saving Week, a joint campaign with the Energy Saving Trust, Department of Energy and Climate Change and Citizens Advice, aims to help people cut their fuel bills and obtain financial support.
There is a growing black hole in our energy bills because we prefer the convenience of standby, but many of us blame each other for leaving things on around the house and it's adding £30 to our bills every year.