Shopping for an energy efficient television set can be difficult. You can scan the manufacturers' specs, but many don't provide power information, and the numbers provided rarely include standby power ratings. Depending on what type of set you buy, a television can consume as little as 45 watts or as much as 500 watts, and cost anywhere from $13 to $145 per year to run. Basically, TVs that use the least amount of electricity are smaller LCD TVs, and the biggest energy consumers are the 50+ inch plasma sets. The most efficient LCD televisions are generally those in the Sharp Aquos line. Last year, CNET tested the energy efficiency of 20 television sets, and the Sharp Aquos LC-20B8U-S 20 inch set was found to be the least power hungry — it costs just $13 a year to run. Rear-projection TVs are also technically energy efficient, but these sets are large and rarely get as bright as the others.