TV wattage ratings

[Hokiefyd]

The old (2005 or 2006) 32" Sharp television we have in our bedroom finally went out. Many years of faithful service (though, if I'm honest, it doesn't have a ton of hours, being only a bedroom TV). We replaced it with a 32" Sharp Roku TV. We really like it -- super crisp display (1080p) and excellent Roku integration.

The screen printing on the back lists it as a 45W power supply inside the TV. The old TV said 170W. That sounds quite high to me (especially the 170W rating). I suppose a television has a relatively steady power supply requirement (unlike a PC, which can vary with differing loads), so I suppose the unit probably runs close to what that stated wattage is, right?

If so, and if these numbers are both apples (to be able to make a direct comparison), it's remarkable how more efficient these displays have become over the years. The 170W unit was a 720p LCD display and the 45W is a 1080p display. Think most of the efficiency gain is due to LED vs. LCD technology?

 

[dishdude]

170 watts for an LCD seems high. I'd expect that for a plasma or CRT.

 

[skyactiv]

I have a 1080P 50" LG Plasma. I have a Kill A Watt meter and measured an average of 340 watts on that display. I also have a 34" Sony CRT HDTV widescreen and it consumes 174 watts on average. My bedroom TV is a 32" Sony LED flat panel that consumes 37 watts on average. My prior bedroom TV was a 20" Sanyo 4:3 CRT which consumed 77 watts on average.

 

[Linctex]

Originally Posted By: dishdude
170 watts for an LCD seems high. I'd expect that for a plasma or CRT.


Agree, though LCD still requires a back light to shine through the liquid crystal. Plasma are much worse.

LED are the least... I think my 32" LED is only 45 watts.

 

[bioburner]

Only one company that attempted to sell 32 inch plasma to my knowledge. I just looked at my old Sharp 2005 24 inch and the power consumption is 84 watts, CFL light source and my Samsung 21 that was just replaced in the kitchen was CFL as well.
Our new idiot box for the kitchen is a 43 inch LG UHD and is at 47 watts
The main Samsung for the AV room is a plasma 65 inch and is balanced at 325 watts. The stereo pulls more than it does

 

[Rand]

Plasma tv's vary greatly with brightness level

my 42" panasonic plasma was between 120w(very dim) 180w(normal-ok for dark room) 305w(cinema bright setting-good for moderate bright room)

The 50" Samsung led lcd that I also have uses 60-115w IIRC.. and its much brighter.
The sports performance is not as good.

Easiest way is to use a kill-a-watts meter, or regular clamp meter.

 

[mk378]

Yes LED is much more efficient. The earlier generation LCD TVs have several CCFL tubes behind the screen that burn steadily whenever the TV is switched on.

Even without a fancy watt meter you can get an idea by holding your hand above the TV after it has been on for a while and notice how much heat is coming out.

 

[itguy08]

It does depend on the image shown and the brightness level. The maximum it can draw (white, 100% brightness, max volume) is what's printed on the label.

CRT's and Plasmas drink the juice when displaying white at a high brightness level. At a dark level or displaying, say dark gray it's less. The bigger the display the more juice it takes.

I think DLP's are fairly constant as the light source is always on at the specified brightness no matter if it's black, white or any color in between.

LCD's (called LED's now but they are the same) used to use what were basically CFL lights to light them. They did use a bit of power (but less than a plasma or CRT) and it was related to the backlight level. LED TV's use less due to the more efficient nature of LED's. Many newer sets use local dimming where they can dim the LED's in dark parts of the scene. This makes the contrast ratio go up and energy usage go down especially in dark scenes.

So it's a combination of more efficient LED's lighting the LCD plus any local dimming that may be used.

 

[kc8adu]

only one i have ever seen was a vizio from 2005.
and the customer still has it and was concerned it may not be repairable in the future since they could not find a replacement.its still good after replacing a bunch of caps 8 years ago and i can repair any board failures but if the panel dies its over.iirc its a fujitsu panel.
rare bird for sure.
Originally Posted By: bioburner
Only one company that attempted to sell 32 inch plasma to my knowledge. I just looked at my old Sharp 2005 24 inch and the power consumption is 84 watts, CFL light source and my Samsung 21 that was just replaced in the kitchen was CFL as well.
Our new idiot box for the kitchen is a 43 inch LG UHD and is at 47 watts
The main Samsung for the AV room is a plasma 65 inch and is balanced at 325 watts. The stereo pulls more than it does

 

[kc8adu]

i will accept the power consumption of my pioneer kuro sets for the image quality they deliver.they see a few hours a week at most.
but these are not a set to own if you play it 12-16 hours a day like many folks do.esp if you live in a hot climate.
then they cost you double.the power they consume and the power your ac uses to remove the heat!

 

[Hokiefyd]

Originally Posted By: mk378
Even without a fancy watt meter you can get an idea by holding your hand above the TV after it has been on for a while and notice how much heat is coming out.


Good point -- yes, these LCDs do put out quite a bit of heat. The two remaining in the house are a 40" Sony and a 37" Sharp, and both are small heaters. The new LED Sharp doesn't seem to put out much heat at all.

Another difference, probably related to this, is every LCD we've had would make that loud "click" when you turned it on or off. I guess that was either the power supply or the ballast or something clicking on and off. Like an old Sony Trinitron monitor. The new LED TV is just like our newer LED computer monitors -- completely silent.

 

[kc8adu]

yes older plasma and some lcd use relays.
1 for power supply soft start and main power on(5v stby always on)
plasma uses another for vs,va on.
its for energy saving.cheap lcd often leave the whole power supply on at all times and just turn off the backlight and processer.

 

[Hokiefyd]

Originally Posted By: kc8adu
yes older plasma and some lcd use relays.
1 for power supply soft start and main power on(5v stby always on)
plasma uses another for vs,va on.
its for energy saving.cheap lcd often leave the whole power supply on at all times and just turn off the backlight and processer.


Yes -- relay. Duh (on my part). You can hear our Sony Bravia in the living room click every now and then, even when it's off. At the same time, probably not by coincidence, it will lose time on its internal clock so that, after a few days, it's 30-60 minutes off from reality. Reset the clock...another day or two later, it's 15 minutes behind.

I suspect the power supply or whatever mechanism in the TV holds the "sleep" power is failing, causing the TV to completely lose power intermittently. No issues, yet, in terms of the TV not working properly.

When it does eventually quit for good, we'll probably replace it with the 43" version of the 32" Sharp/Roku we just bought.