Should TVs have video off?

[Dave2002]

I sometimes use TV to listen to radio - R3 and suchlike. If I use our large LCD it consumes 150 watts, though smaller 19 inch models only use 25 Watts. Some with plasma screens will use even more.

Maybe manufacurers should consider a video off option to save power. This would also be useful for TVs which might be used to contol a computer based audio system.

I've not seen a TV with such an option.

I am, of course waiting for someone to tell me I should get up and turn on my FM portable and save energy that way! Currently the portable is elsewhere, so it'll have to be either DAB or computer I'm afraid, and some of the computer options use more power than a small TV.

Lovely Schumann with the Nash Ensemble on Sat morning (25/8). BTW - via Freesat. Märschenbilder - CDA69723.

[Northender]

I'm pretty much a complete ignoramus when it comes to technology, but can I not reduce my consumption of power if I press the green 'screen saver' button on my remote while listening to the radio, or indeed a CD, via the TV set?

[MrGongGong]

Have you done the maths ?
(not that I have )

from my rather rusty O level Physics I seem to recall that what DOES use current is a transformer or heating element or motor etc
not sure how much current the LCD or LED screen pulls

you might only save factions of a penny in a hundred years !

[Petrushka]

I have R3 coming from the tuner in my DVD recorder via the hi-fi so bypassing the TV altogether.

My physics knowledge is practically non-existent but Mr GG's comment makes sense to me.

[mangerton]

Have you done the maths ?
(not that I have )

from my rather rusty O level Physics I seem to recall that what DOES use current is a transformer or heating element or motor etc
not sure how much current the LCD or LED screen pulls

you might only save factions of a penny in a hundred years !

A plate on the back of the set tells me that my Samsung 32" LCD screen TV consumes 120 watts. All electrical appliances are marked with this information. The TV has a means of switching the screen off (in the settings menu) so that power can be saved when listening to radio. As I don't have an AC ammeter I don't know how much, but I expect the screen consumes by far most of the current drawn, especially as I don't usually use the TV's loudspeakers.

I've just done the sums, and my TV costs approx 1.4p* per hour to run, so I reckon switching the screen off when not in use does give measurable savings.

* For pedants, this is the marginal cost, and takes no account of the higher unit cost I pay in lieu of a standing charge.

[Ferretfancy]

It is suggested by the manufacturers that it's not a good idea to leave a still image on the screen for too long, as it can leave a permanent image. i don't think this should be a problem with channel logos, as the background to them is changing with the picture behind them, none the less it makes sense to listen to sound only when you wish.

Like Petrushka, I feed a digital output from my hard disk recorder into the hi-fi. After selecting the station I switch off the TV, and of course with Freeview I can record radio programmes in advance.

[Simon B]

but I expect the screen consumes by far most of the current drawn

Correct, the power dissipation of any TV (including old fashioned cathode ray tube TVs as well as LCD/plasma) will be absolutely dominated by the display.

Analagously, if you have a smartphone or a laptop and want to make the battery last longer, the most immediately effective measure is to turn the brightness down on the display. It's not a perfect analogy as (at least in the case of the laptop) a rather greater proportion of the power will be dissipated by computation-related things - the processor chip(s), spinning disk drives, cooling fans...

[Dave2002]

Have you done the maths ?
(not that I have )

from my rather rusty O level Physics I seem to recall that what DOES use current is a transformer or heating element or motor etc
not sure how much current the LCD or LED screen pulls

you might only save factions of a penny in a hundred years !

No - I think the savings could be considerable, given enough time, particularly for large LCD, LED or plasma screens. As mangerton suggests, a 120-150 Watt TV should cost about 1.4p/hour, though some TVs consume about 1/6 of that e.g 19 inch LCDs from Tesco. I didn't just do the maths, I measured the consumption.

Re transformers, things have moved on. Many devices, particularly digital circuits and small pre and power amplifiers, use switched mode power supplies which are rather efficient, and waste hardly anything if there's minimal load. However for audio work some enthusiasts don't like switching psus. Listening to radio via TV is in most cases going to be a compromise though anyway, re audio quality. Sometimes it's good enough. I don't know what the power arrangements are inside modern TVs, but I doubt that they have those chunky and heavy transformers of yesteryear.

It's possible that some TVs may blank the video automatically if they detect there's no video, but I don't think they all do that.

[Vile Consort]

A good rule of thumb is that, if it gets hot or warm air comes out of it, it's using a lot of power; if it runs cold, it isn't. Hence all the fuss about phone chargers is utterly misdirected.

You can, of course, buy plug-in power monitors such as this one which will tell you how much power a single appliance is using.

I think back to my grandmother's house when I was a lad in the 60's. The only appliances she had were two reading lamps, the radio and the television. When she went to bed, she unplugged them. There was, of course, no question of leaving any lights on overnight, so the overnight power consumption was zero.

The old lady who lived next door to her did even better; there was a street light directly outside her bedroom window, and she went to bed by its light. When the bulb went she was on to the council in a flash!

[Dave2002]

It's worth remembering ... and reading, James Thurber - http://downwithtyranny.blogspot.co.u...-times_06.html

[Eine Alpensinfonie]

It is suggested by the manufacturers that it's not a good idea to leave a still image on the screen for too long, as it can leave a permanent image.

On Freesat radio, you can press the green button for a screen saver. The screen-burn problem is most serious with plasma screens (as is fuel consumption) but the picture is just stunning.

[Resurrection Man]

Quite a few plasma screens have an option to ever so slightly move the displayed image around ....not so you'd notice..but enough to prevent problems.

.....
you might only save factions of a penny in a hundred years !

Spot on and not that far removed from the nonsense that Building Regs heaped on us with Windows Energy Ratings. The microscopically small incremental changes brought about compared to the downsides...huge glazing bars, aestheticlly ugly windows, higher manufacturing cost etc.....doesn't bear rational consideration. It was just a whopping con perpetrated by the plastic double-glazing companies.

[Dave2002]

Spot on and not that far removed from the nonsense that Building Regs heaped on us with Windows Energy Ratings. The microscopically small incremental changes brought about compared to the downsides...huge glazing bars, aestheticlly ugly windows, higher manufacturing cost etc.....doesn't bear rational consideration. It was just a whopping con perpetrated by the plastic double-glazing companies.

No - not spot on at all. Good double or triple glazing really works, and either reduces the energy consumption or increases the comfort inside well insulated buildings.

This is likely to be more critical in cold winters, or possibly also hot summers. Lucky for you if you live somewhere which doesn't have significant weather variations and is comfortable to live in with minimal shelter.

If you don't believe me come and sit in my single glazed and dilapidated conservatory, though you may miss the opportunity as I'm hoping to replace it soon. I agree that sometimes one may have to make a more complex decision based on balancing aesthetic appearance against energy used etc., particularly for those who have elegant or listed buildings. Also, you don't have to have plastic double glazing.

[Don Petter]

On Freesat radio, you can press the green button for a screen saver. The screen-burn problem is most serious with plasma screens (as is fuel consumption) but the picture is just stunning.

Of our three Freeview boxes, the recently bought cheap Goodmans one changes to a slow-moving screen saver on radio, though the old cheap Wharfedale, and the new not-cheap Humax PVR just display the static logo and information image.

[Bryn]

About 21 months ago I treated myself to an LG 50PK590. That does indeed have a video off function via the energy saving menu. I use it on those occasions I listen to the radio via freeview, and sometimes for television broadcasts of music, too. The audio is fed through the hi-fi, of course. I would be very much in favour of all new televisions having such a 'screen off' facility.