Its report, "The Ampere Strikes Back," said new devices are often more power-hungry than earlier models and many are left on standby rather than being switched off. Some don't even have an "off" button.

"Not only are there many more devices in the typical home, but many of them are in a permanent state of readiness to swing into action," the report says.

In 1982, only three percent of homes had a personal computer compared to 60 percent today. Similarly, printer ownership has shot up to 58 percent from 0.7 percent.

Houses often have more than one TV and people are buying more large screen sets that use more energy, the report says.

By 2020, televisions on standby will consume 1.4 percent of all domestic electricity, the report predicts.

Despite attempts by some manufacturers to make more energy-efficient products, some digital radios still use four times as much power as analogue sets, the report says.

The growth of single person households -- many with big TVs, set-top boxes, computers, games consoles, TV and music recorders and digital radios -- will add to the higher energy consumption.

The trust said households could save 37 pounds a year on their energy bill by switching devices off at the wall.

"Think about how you are using appliances and turn equipment off when not needed as well as rein in the impulse to hoard equipment that has already been replaced," said EST Chief Executive Philip Sellwood.