Samsung Electronics has denied allegations that it designed its TVs to consume less energy during tests than they do in real-world situations.
The allegations, in a report by The Guardian, center on a feature Samsung calls "motion lighting," which it introduced to its TVs in 2011.
Some Samsung TVs in Europe appeared to use less energy during independent laboratory tests than they do in real-world conditions, the newspaper reported, saying this raised questions about whether they had been programmed to game energy efficiency tests.
Responding to The Guardian's report, Samsung said "Motion lighting helps save energy in real life. [...] It is a standard out-of-the-box feature, which is switched on when the customer takes delivery of their TV, and remains on whenever the customer chooses to watch their TV in Standard viewing mode."
In the European Union, tests of TV energy consumption are performed in the device's "standard" or "home" settings mode -- even if that setting is one that many users are likely to want to change for one that consumes more energy.
Samsung's motion lighting feature saves energy by dimming TV screens when moving video is detected -- exactly the kind of situation in which ordinary users are likely to want their screens to stay bright, so they can watch them.
Disabling the Motion Lighting function to make the image more watchable is a popular tip in TV forums.
It's even offered as advice by Samsung's own U.S. support site, which on a page dated Sept. 23, 2013, advises: "If the brightness on your TV changes automatically (randomly dims and brightens) you may need to adjust the ... Motion Lighting Function."
Nevertheless, Samsung maintains it is not a test-cheat, because "Motion lighting is not a setting that only activates during compliance testing."
Viewers don't even need to explicitly disable motion lighting to lose its energy-saving benefits. "If the customer chooses to alter their display settings or switch to a different mode then the feature switches off, which gives our customers a simple choice of whether they choose to prioritise power efficiency or performance in their TV," Samsung said.
Switching to a different mode -- recent models feature Standard, Dynamic, Movie, or Entertainment modes -- is something many users will do, but even something as simple as changing the contrast could be enough to disable the setting.
CompliantTV, the European Commission-sponsored project that coordinated the tests referred to by The Guardian, published a report on its testing activities in February, in which it noted: "The laboratories observed different TV behaviours during the measurements and this raised the issue of the possibility of the TV to detect a test procedure and adapt its power consumption accordingly."
The manufacturers concerned were not named in this report, but Samsung was identified as one of them in unpublished lab tests, The Guardian said.