Electricity Use

[CraigD]

I'm amazed at the fact that the LCD TV ate more (considerably more) juice than the CRT - I was planning on getting me an LCD because it made sense to me that it'll eat way, waaaay less power than a cathode tube. But there goes that idea. Maybe people should be told about this... :eek_big:

In fairness to the LCD TV, the Samsung a900 is much bigger (40” diagonal HDTV 16:9 , ie: 35 x 19.7”) than the JVC AV-27D303 (27” NTSC 4:3, ie: 22 x 16.5”), and much brighter (1300 cd/m^2 vs. 300 cd/m^2). So, showing a white screen, the big TV is putting out about 8 times as much light.

 

A 900 lm 17 W compact florescent bulb has a brightness of [math]\frac{900}{4 \pi} \dot= 72[/math] cd, so at 240 W max, the Samsung is 57% as efficient – not bad for something much more fun to watch than a florescent bulb ;). By comparison, the JVC is only about 31% as efficient.

 

Also, note that this LCD TV’s power varies a lot, depending on what it’s displaying, from 180 W for a dark image, to 240 W for a bright one. The CRT seems to draw about the same power no mater what it’s displaying.

 

At 1300 cd/m^2, the Samsung a900 is an unusually bright TV, about 3 times brighter than some models. This was one of the reasons I bought this model – the main room where it is used has many large windows, and tends to be very bright during the day. The JVC CRT TV it replaced could be difficult to view on bright days with open window blinds, while even when places in nearly direct sunlight, the Samsung gives a clear (and owing to the matte finish common to LCD TVs, but not plasmas or CRTs) glare-free picture.

 

My greatest surprise with my first and so far only large flat-panel TV is that it generates a good bit of heat, enough to be felt with an open hand and registers a couple of degrees C higher near the TV than elsewhere in the room.

 

There are some very energy inefficient large flat panel TVs on the market, and manufacturer’s specifications rarely provide accurate power data, so such purchases need to approached carefully. A easy-to-use meter like the Kill-A-Watt and a trip to a large TV store – though you may have to argue with the staff over using it – is a handy approach.