Per Capita Davis: How much energy does your TV use?

This post by John Mott-Smith, a member of the Cool Davis Initiative is cross-posted from the Davis Enterprise where this originally appeared.

A statistic can be revealing — conveying in a number what it may take paragraphs to describe in words. Of course, statistics also can be deceptive. A statement (usually) attributed to Mark Twain sums it up, so to speak: “There are three kinds of lies: lies, damned lies and statistics.”

It used to be that the aphorism “A picture is worth a thousand words” captured the belief that what we could see with our own eyes carried more information and truth than words or numbers, but that was before Photoshop.

At any rate, below are a few statistics, some of which may benefit from augmentation with a dash of salt, but which serve as a doorway to a discussion of televisions and energy use.

“An estimated 5.1 million Americans bought new TVs in anticipation of last Sunday’s Super Bowl.” This was an unattributed statement in an article generally focused on efforts to recycle older-model televisions.

In terms of consumerism and its effect on energy use, the 5.1 million number struck me in two ways. First, it was relatively precise; if it was just a guesstimate or a made-up fact, one would expect it to be rounded off to 5 million, or modified by the ubiquitous “more than.” Second, assuming it’s true, or even near true, what does this mean energy-wise?

How much energy a TV uses is defined mostly by four factors: how big the screen is, what technology is used to provide the picture, the settings on the TV itself for contrast and brightness, and what other devices are plugged into and used with the TV.

In terms of size, big screens use more energy than smaller screens although, interestingly, the big ones may use less energy per square inch; they just usually have more square inches, sometimes a lot more.

How much energy a TV uses is defined mostly by four factors: how big the screen is, what technology is used to provide the picture, the settings on the TV itself for contrast and brightness, and what other devices are plugged into and used with the TV.

In terms of technology, according to one report from an independent evaluator, plasma screens use roughly two to three times more electricity than LCD (liquid crystal display) sets, largely because — get ready for a stupendously oversimplified explanation — plasma technology relies on millions of “cells” in the screen itself that act as tiny light bulbs and, as we all know, the more light bulbs you have, the more energy you’re using.

LCD technology, on the other hand, uses a single light source behind the screen and, if this source is an LED (light-emitting diode) it can be (relatively) more efficient.

When it comes to picture settings, store displays may have the brightness /contrast controls set at high levels that optimize the appeal of the product, but once you get the TV home, these settings can be lowered to substantially cut energy usage (by as much as half) with minimal loss of picture quality. It’s sort of like using a dimmer switch.

Lastly, or at least fourthly, the amount of energy a TV uses depends on what devices are plugged into it. A recent PG&E study found that about 10 percent of electricity used in homes is associated with the TV, and a lot of this comes from ancillary usages of the TV such as DVR recorders, DVDs, gaming consoles and satellite receivers.

Or, one I had never heard of before, Slingbox, a system that encodes visual and audio from your TV into something that can be sent over the Internet anywhere in the world, so you can watch, for example, reruns of Marlin Perkins and “Mutual of Omaha’s Wild Kingdom” on your PC, Mac, iPhone or other device while sitting by the pool while on vacation in Spain.

There may be a fifth factor as well: when the television was bought. Apparently, the Energy Star labels used to inform customers about relative energy efficiency did not, prior to 2008, test TVs when they were turned on and operating: the label could be attained just by testing the TV while it was in standby mode.

Energy Star has upgraded its standards several times, but the real improvement from the point of view of wanting to be an informed customer may come from two other directions — first, a proposed labeling requirement that actually indicates how many watts the TV is drawing and, second, from a new set of state standards (California leads again) set to go into effect in 2013.

As an aside, if you are curious about how much electricity your TV is using, you can find out, not just approximately by reading a chart that gives you estimates of averages, but by going to the Yolo County Library on 14th Street and checking out, as you would a book, a “Kill-A-Watt” meter. You can take it home for a couple of weeks.

The meter comes with easy instructions. All you have to do is plug it into an electrical outlet, plug your TV into the meter, then read how many watts the TV is using when in normal operation, when it is off, and when games or other devices are plugged in and being used.

Of course, this meter also can be used to measure wattages of other household gadgets and some appliances.