Perhaps you have heard of Moore’s Law. Named after the founder of Intel, Gordon Moore, it states that computing power of integrated circuits doubles every two years. In the latest issue of the Mail & Guardian, I have introduced what shall heretofore be known as Boroughs’s Law. Named after the founder of Greenerhouse, Don Boroughs, it states that for each additional ten inches in flat-panel television screen size, its electricity consumption approximately doubles.

I discovered this law by plotting the consumption of TVs sold in South Africa on a graph, and it’s the most important thing you need to know when buying a television. Because just to look at it, you might think that a 50 inch TV—manufacturers measure these things on the diagonal in inches—would use 20 percent more electricity than a 40 inch TV. You would be wrong.

Forty-inch TVs shouldn’t use more than 250 watts. (The worst ones use more.) Fifty-inch TVs typically use 500 watts, more than six 60-watt lamps. Boroughs’s Law works all the way through the range of television sizes available in South Africa, from 20 inches to 60 inches.

This tells you that the first thing to do is when buying a television is to convince your partner—or yourself—that you can get by with a TV one size smaller than the one you have been considering. A 32-inch LCD TV, which would have been considered large not many years ago, should use a reasonable 150 watts. That’s not much more than the average large CRT TV—the kind of TV we’ve all been using for the past few decades—and even less than the least efficient CRTs. (Cathode Ray Tubes.) Sony sells a 20-inch LCD which uses an amazing 60 watts. The incredible efficiency of LCD screens at small sizes—and only at small sizes—explains why they are the greenest choice for computer screens.

Once you have decided on a size, there is still a wide range of power consumption, even within the same brand of television. Thirty-two inch TVs, for example, vary in consumption from 132 watts to 380 watts. Televisions should come with big labels stating their consumption, and one day they will. In the meantime, there are only two ways of learning the wattage of a television: through the internet or checking the label on the back of the TV. If you are researching from home, try these websites:


www.philips.co.za
www.sony.co.za
www.samsung.co.za

Once you find a TV that interests you on the web page, click on “technical specifications,” or similar wording. The wattage is usually hidden near the bottom of the list.

You should be able to find a 32-inch TV using 140 watts, a 42-inch screen using 240 watts, or a 46-inch model using 270 watts. LCD TVs tend to use less electricity than plasma TVs. If you really feel that you must have a larger TV, the only models that use acceptable amounts of power are rear-projection TVs. Experts say that their picture quality is as good as flat-panels, they cost a lot less, and the Sony models use about 200 watts, all the way up to a 60-inch screen. They are bulkier, however, and will not be available for too much longer, as they are losing the battle for market share. This may lead to close-out bargains.

If you don’t want to sift through a hundred models, I suggest starting with the Philips brand, as they tend to be more energy efficient. I would avoid LG, as they tend to be more power-hungry and they often don’t state the wattage on the label at the rear of the TV. If you like Sony, and money isn’t much of an object, the European Imaging & Sound Association gave its most recent Green Television of the Year award to the Sony KDL-40D3000. That exact model isn’t available in South Africa, but its local equivalent is the 40-inch D Series Bravia model KLV-40D300A, which uses 180 watts.

Their voting panel looks at ease of recycling and other environmental issues in addition to electricity consumption, so this should be an all-around good choice if you need a big TV.

Or of course you could just stick with your existing CRT television. I checked my 2-year-old, 29-inch Philips CRT television, and it uses 73 watts. If you use an older TV, it is doubly important that you switch it off at the box, rather than using the remote to put it into stand-by. (This also reduces the chance of damage from a lightning strike.) Almost all new flat-panel TVs use one watt or less in stand-by, but older TVs draw enough power in stand-by that in a day you may use more electricity not watching TV than you do watching it.