BERLIN — While very other appliance in the home has been redesigned to save power, televisions seem to have escaped the trend. New flat panels have actually evolved into disgraceful electricity gluttons.

In theory, liquid crystal displays (LCDs), the most common type of flat screen, need less electricity to create a moving image than the old cathode-ray-tube (CRT) televisions that they are gradually replacing.

But as Paul Gray, a British analyst at the Display Search consultancy, explains: “Consumers took advantage of other benefits like their wonderful thinness to buy larger screens. And it’s generally true that lar­ger screens use more power (than smaller ones).”

Years ago, most living rooms had a 20-inch television facing the couch. But the size, which measures the diagonal width of a screen, has been creeping up.

“At the present day, 32-inch is a mainstream size,” said Gray. “There has been a huge increase in screen area.”

The way an LCD panel works is also a cause of the problem. The panels are made up of a backlight, which shines a constant white light, and the actual electronic screen, seen by the viewer, which filters out some of the white light to create a co­loured image.

“Only about 20% of the light comes through to your eyes,” said Gray.

“Most LCDs use the same amount of power whether they are displaying white or black.”

Regulators in North America, Europe and Japan are concerned and are already taking action.

The European Union has issued a directive requiring televisions sold after April 1, 2012, to offer a 20% cut in power consumption compared to today’s average.

One technology to fix the problem already exists and is found in the screens of some portable notebook computers: the LED (light-emitting diode) backlight. It is set to replace the cold cathode fluorescent lamp (CCFL) used currently to shine light through LCD screens.

Japanese television maker Sharp is releasing a range of LED-backlit models that are priced to appeal to middle-class consumers in its North American and European markets.

“We believe that by December this year, one in every eight televisions sold in Germany will have an LED backlight,” said Sharp’s chief for Germany and Austria, Frank Bolten.

He predicted 30% of Sharp televisions sold in Germany this Christmas will have the technology.

Dutch-based manufacturer Philips is also launching a range of mass-market LED-backlight televisions this year, and LG of South Korea is to test the water this autumn with a 55-inch TV using the technology.

The products are expected to be the big attention-grabbers at IFA, the annual consumer electronics fair, which begins on September 4 in the German capital Berlin.