LCD and plasma TVs: FAQs
Are LCD and plasma TVs as reliable as conventional televisions?
LCD and plasma are too new for us to have information about their long-term reliability. Their durability is also a bit of an unknown quantity.
Which uses more power – LCD or plasma TVs?
Plasma TVs use more power than LCD TVs
On average, plasma TVs use more than twice the power of 32-inch LCD TVs and 2.5 times as much as conventional 32-inch widescreen televisions.
Even when comparing like-for-like in terms of screen size, on average plasma TVs use around 50% more energy than similar-sized LCD TVs.
However, some manufacturers point out that the power use of a plasma TV is directly dependent on picture brightness, whereas an LCD TV picture requires a constant source of illumination.
The theory goes that a plasma TV should use less power over time. But in reality, plasma TVs require significantly more power to achieve the same brightness level as an LCD TV, putting something of a 42-inch widescreen hole in the theory.
Which? technology email
Weekly gadget news
direct to your inbox
- Exclusive video previews
- Expert buying advice
- Hot money-saving deals
- Win an iPod Touch
sign up 
Does the size of the television screen significantly influence power consumption?
The smaller the TV screen, the less power it uses. On average, a 26-inch LCD TV screen uses less than 90 watts when switched on and costs £20 a year to run. A 40-inch LCD TV uses twice the power and costs twice as much to run.
But combine plasma technology with huge TV screen sizes (50 inches), and we've seen sets that consume more than 400 watts, and would cost more than £100 a year to run.
What is high definition TV?
HDTV is much sharper and more detailed than regular TV, and boasts more realistic pictures. It's available either via Sky or Virgin subscription packages. Alternatively you can pick up a couple of HD channels on the new BBC/ITV Freesat service, without the monthly payments.
Whatever digital platform you choose, to watch high definition you'll also need a high definition TV. Look for the official HD-ready logo when buying an LCD or plasma TV – this guarantees the minimum screen resolution and digital sockets needed to watch HD broadcasts. For more on selecting an HDTV, see our guide to choosing a high-definition TV.
Are there different types of high-definition signal?
HDTV pictures come in two main formats – 1080i and 1080p. The four-digit number tells you how many horizontal lines make up the picture, and the letter shows how it's broadcast. The 'i' means the picture is 'interlaced' and sent to the TV in two sequences, one after another, and the TV meshes them together.
HD broadcasts are in 1080i but high-definition Blu-ray players use the 1080p format. A 1080p picture is sent in a single sequence making the picture sharper than 1080i – but the difference is very subtle.
Can I watch high-definition DVD on an HD-ready LCD or plasma TV?
Most new HD-ready TVs can now process a 1080p signal, so will work fine with Blu-ray players. Older HD-ready TVs and many cheaper TV sets may not process 1080p, but will simply switch to 1080i when used with high-definition DVD.
The best TVs will also display pictures, or frames, at the same rate they're recorded onto high-definition discs (24 frames per second). If the TV doesn't process at the same speed, the result can be juddery movements during fast-motion or camera-panning scenes.
The official logo
How do I know which LCD and plasma TVs are best suited to high-definition DVD?
Look for LCD and plasma TVs with the new HD-ready 1080p logo – this guarantees 1080p output, 24fps and a high screen resolution of 1920x1080. It increases the chances of getting the best possible high-definition Blu-ray DVD picture but is not an absolute guarantee.
Most new HD-ready TV sets will also process a 1080p signal at 24 frames per second – so will work fine with Blu-ray players. HD-ready sets lack the higher screen resolution of 'HD-ready 1080p' TV sets, but this is not as vital as it may seem.
Many older HD-ready TVs will not process at either 1080p or 24 frames per second, increasing the possibility of jerky movement on panning or motion scenes.
What about LCD and plasma TVs with labels like HDFull or 1080HD?
Labels like Full HD or 1080HD are not part of an official standard, so meanings differ between manufacturers. Some can process a 1080p signal, others have a high screen resolution of 1080 horizontal lines (1920x1080), some do both.
When are we likely to see HD on Freeview?
Plans are afoot to launch HDTV channels on terrestrial Freeview – many technical issues have been resolved and there’s even a chance it could happen over the next couple of years. The satellite equivalent of Freeview is called Freesat. For a one-off payment (for the set-top box and dish) you can receive free HDTV channels.
Can terrestrial IDTVs pick up Freesat or even terrestrial HD broadcasts?
No. IDTVs will need another decoder (or set-top box) to receive terrestrial or Freesat HD signals. Terrestrial digital will, in that respect, be no different to cable or satellite digital, which also require another decoder box. Of course, the TV has to be HD-ready to display HD programmes.
Will my IDTV become obsolete if terrestrial HDTV is launched?
No. If terrestrial HDTV is launched, standard definition content will still be broadcast in the same way. So your current IDTV or set-top box will be able to receive signals as normal. However, they won't be able to receive terrestrial HD signals.
Wall brackets usually have to be bought separately
Can I hang my LCD or plasma TV on the wall?
Most LCD and plasma TVs can be mounted on walls. However, most don't come supplied with the wall-mounting kits required.
These have to be bought separately and (depending on the size of your TV) can cost anything up to £300. Most TVs and kits match the Vesa standard – a set of industry-wide measurements.
Do I need a set-top box to get digital TV on my LCD or plasma TV?
No. The vast majority of new TVs are integrated digital models (IDTVs) and feature a built-in digital tuner to receive digital TV signals. The vast majority are Freeview IDTVs (digital channels through your normal aerial), but Freesat (via satellite) IDTVs are now being launched . Go to our digital switchover page to find out more about Freeview, Freesat and the different ways to receive digital TV.
What is audio description?
Audio description is an additional narration for visually-impaired people that describes significant visual information, such as body language and scenery. The service is available on Sky and Freeview.
Some of the best LCD and plasma TVs (mostly Panasonic and Sony) can decode audio description on Freeview. A schedule of Freeview programmes with audio description on the DTG website.
Can I record audio description?
To record audio description, a DVD recorder is your best option – but be aware that the audio description track will be permanently recorded on to the disc. We have yet to see a PVR that can decode and record audio description.
Does the quality of my Scart cables matter?
Cable quality can influence sound and picture quality on LCD and plasma TVs. Poor-quality Scart cables are more prone to interference from other devices and atmospherics. But you don’t have to pay the earth – a tenner should do, rather than opting for the cheapest at three or four quid.
A good rule of thumb – the thicker the cable the better. This usually means it boasts more ‘screening’ from interference. Also look for gold plated connectors.
Occasionally plug and unplug the cables in your LCD or plasmaTV. This helps to remove the build-up of oxides, which affect how well signals are transmitted.
What is screen burn and does it affect new LCD and plasma TVs?
We've found screen burn is no longer the issue it once was
Screen burn is where a ghost image of a channel logo is left on the television screen once the set has been turned off or onto another channel. The problem doesn’t affect LCD TVs, but plasma TVs and old fashioned CRT TVs are susceptible.
However, broadcasters have toned down the brightness of their logos, and the latest plasma TVs boast screen-cleaning technologies to combat the problem.
In Which? tests, images burnt on to the plasma TV screen after a day, disappeared after normal TV viewing. After leaving a channel logo on-screen for a week, only one plasma TV (out of six tested) suffered any permanent screen-burn.
Is it true that new technology LCD and plasma TVs have a problem with the sound and pictures matching up?
The LCD and plasma TVs in the Which? tests haven't shown this problem. Internal speaker output is properly aligned with the pictures on the TV screen.
We’ve occasionally found some discrepancy when linking LCD and plasma TVs up to external loudspeakers in the laboratory, but this wouldn’t be apparent in everyday use.
For more advice, check our guide to buying TVs.