LED, LCD and plasma TV: How we test TVs

Which? test lab

Which? tests almost 3,000 products every year, including more home technology products than anyone else. We look at new products as soon as they are announced, helping you to understand new technologies, and whether they are worth your money.

Which? tests LED, LCD and plasma TVs every month, reviewing over 100 a year and covering virtually all the bestselling models from the leading television brands.

Which? is different because...

• Our tests are based on years of testing experience
• We don't accept adverts in our magazines or website
• We buy everything we lab-test
• We're completely independent of any manufacturers

Which? exists to give consumers impartial advice, which means that if a product isn't any good we'll say so, without fear of penalty. Which? works for you, providing trustworthy advice without a hidden agenda. We examine everything that matters across all products, including performance, features and how well they work in real life – so you'll know exactly what to expect. Our unique, comparative lab tests mean you can trust our Best Buy and Don't Buy verdicts and choose with confidence.

Our experts examining picture quality in our viewing test

TV testing in brief

Which? tests around 100 TVs a year and we ensure that our guides only have the models that are currently available.

Which? tests LED, LCD and plasma TVs every month, covering virtually all the bestselling models from the leading television brands. Each TV is put through an extraordinary six-week test – a mixture of expert panel assessments and technical laboratory testing – scrutinising everything from picture and sound quality to energy efficiency and ease of use.

We aim to ensure all the major brands are represented.

How we choose products for testing

Dedicated Business Researchers carefully select the products Which? tests, scouring the market for the latest releases and the most innovative products. Our Business Researchers aim to cover a very high percentage of the market in any one product area. And, while we do test some premium products, we avoid testing those products which you would need a second mortgage to afford. We take the following criteria into account when choosing TVs:

• Popularity – we test TVs that are the biggest sellers

• Brand reliability – we test more TVs from brands that are reliable

• Innovation – we test new and innovative TVs

• Cost – we typically test TVs that cost between £250 and £1250.

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Ease of use

Our expert assessors test our products for their ease of use by running through everyday scenarios that replicate how you use your TV.

Initially we look at setting up the TV for the first time and connecting up all the cables and tuning it in. All the TVs in this review tune themselves, so you don't have to fiddle around looking for the best reception.

The Electronic Programme Guide (EPG) shows you what’s coming next on each channel, and is checked for its accessibility. Other on-screen menus are also tested including advanced picture and sound settings and any recording functions so you don’t get lost while searching though poorly constructed menus.

Remote controls put you in control of your TV, so they’re fully tested for their layout, functionality and any unresponsive buttons. Our experts also assess the front-panel controls, instruction manuals, accessibility of the sockets, and new and upcoming features such as internet TV which allows you to view websites such as YouTube and downloads apps.

We also consider how comfortable products are to use for those with manual dexterity problems, taking advice from our sister organisation Ricability.

Technical testing

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Our products undergo an extensive range intensive objective laboratory testing to assess performance.

Picture quality

Which? conducts many technical tests and uses an independent expert viewing panel to assess picture quality under the same conditions in a dimmed, tungsten-lit room. Brightness and contrast levels are set as equally as possible, and the LED, LCD and plasma TVs on test all receive the same-quality picture signal. The same experts take part each time, and we conceal brand names.

We show a series of standard-definition video clips – each helps the experts assess a different aspect of picture quality, e.g. a moving train helps highlight problems with panning and movement.

We also watch digital Freeview to see how the TV copes with a lower-quality broadcast signal. High definition is assessed via 1080i Freeview HD and 1080p Blu-ray DVD discs. We also check to see how well the TV 'up-scales' standard definition programmes and a series of 3D Blu-ray and Sky 3D clips are used to assess 3D picture quality.

Each image is awarded an individual score, and each LED, LCD and plasma TV an overall picture score. The best TVs offer a good compromise between different viewing demands.

Sound quality

Due to their thin design, many new TVs suffer from small and weak speakers which can really dampen the viewing experience. Our experts listen to, and score, male and female voices, classical music, pop music, jazz and a TV drama under controlled conditions.

Benchmark samples from previous Which? TV tests are used to ensure continuity. Technical assessments include measuring the characteristic background noise (e.g. a low-level buzzing) and the maximum sound levels from the internal speakers before they show deterioration in sound quality.

Try Which? today for just £1 to find out which tablets we rated as Best Buys.

All our TVs are rated for energy use

Energy use

We check all TVs for energy use to make sure that they do not cost you, and the earth, once they are plugged in.

Which? tests the energy use of each TV in a variety of viewing modes and estimates the annual running costs, that lead to our energy use star rating.

Our experts helped establish the latest international standards for measuring LCD and plasma TV energy consumption, and we use these as the basis for our tests. Using standardised video footage, power consumption readings are taken in 16:9 (widescreen) mode with the TV settings as delivered.

However, we actually exceed the minimum standard and take further readings for each TV while using a moving test pattern. We also check everything in 4:3 (old box shape) mode and then do the whole test again. We then take measurements five minutes and two hours after switching into standby.

To assess the efficiency of any power-saving light sensor, we take measurements in three typical living-room environments; bright daylight, dimly lit and, for horror movie fans, in the dark.

Our experts have found that adjusting the TV's settings (see 'ideal settings' within the reviews of each LCD and plasma TV we've tested) can reduce power usage considerably.

Look out for for our 'Energy Saver' logo which is awarded to Best Buy products we find to be the most efficient in their class.

Ratings explained

All data sent back from our laboratories is carefully analysed by Which? staff so that the highs and lows of every product are revealed. If anything does not add up with a product then we will retest it. If there's a fault we'll purchase a new product to see whether it’s a one-off issue, or symptomatic of a larger problem.

The TV score ignores price and is based on: