As the cost-of-living crisis bites, and households look for any opportunity to cut the bills, headlines suggesting consumers can save hundreds of pounds just by turning off unused chargers have been an appealing prospect. But, experts say, such claims about "vampire devices" are actually more like a zombie statistic.
"Things have dramatically improved since those studies were first carried out," said Craig Melson, an associate director for climate, environment and sustainability at techUK. "Processors are low-power, screens have switched from LCD to LED technology, fridges and washing machines have become more efficient. Technology is just more miniaturised, more efficient, using better processors - and, crucially, they are more adaptable as well."
But that statistic came from a 2015 report from the US National Research Defence Council, based on analysis of homes in California. "Think about the laptop you used 10 years ago," Melson says: "That might need a big ugly plug in the middle, a big transformer. By and large, now you can just plug them straight into USB-C: that is much more energy efficient, and there is no need to draw power."
As well as being seven years old and based on another country's energy, consumers may struggle to make some of the suggested savings: a third of the "always on" electronics identified in the study are "recirculation pumps, fishponds, aquariums, and protected outlets in bathrooms, kitchens and garages." Consumers who switch off their aquarium at night can save money but their fish may object.
Other devices included in the 23% figure are left on because they are intended to run all the time: wifi routers and electric space heaters or air conditioning units increase the electricity used by a home but provide benefits while doing so.
More importantly, Melson notes, American consumers are not covered by the array of European regulations that have slashed power use for British consumers. He said: "The eco-design directive, European regulation, has driven design changes across the sector. It's much more regulated, and business practices have evolved."
The US report that first found the 23% figure even highlights the advantages of European regulation: "The European standard addresses a large portion of the idle load issue highlighted in this study," the American researchers say.
Other claims of "vampire devices" reach even further back. In October, the UK's Energy Saving Trust claimed a modest £35 saving from turning off devices on standby each year, citing a 2013 report that itself accounted for the energy use of devices including a VCR, largely discontinued in 2004, and a PlayStation 2, first produced in 2000.
For consumers who want to save electricity, Melson says, a better focus is to examine the "eco mode" settings on devices such as TVs and games consoles, turning off features such as auto-updates to reduce the standby use further.
British Gas did not reply to requests for comment.
