Is Your PC or HDTV an Energy Hog?

The Samsung LN55A950 is a 55-inch LCD TV, and the first that PC World has tested with LED backlighting. This feature adds greatly to the TV's price, but the manufacturer claims that it is more efficient than traditional backlighting. This HDTV did yield pretty good numbers in our energy tests. The LN55A950 used 38 percent fewer watt-hours than most of the 50-inch HDTVs we've examined (the group's average was 18.6 watt-hours). In general, LED backlighting shows significant energy savings as well as being more environmentally friendly on several other counts.

The 50-inch Panasonic TH-50PZ850U plasma HDTV has a number of interesting features. It can display pictures and run videos that have been stored on an SD card via its SD card slot. You can also plug the TH-50PZ850U into an ethernet connection and play Internet video. The HDTV does a decent, though not extraordinary, job of displaying movies and TV shows. However, in our energy tests, this Panasonic model used 43 percent more energy than the average of the HDTVs of similar size that we've seen.

Let's look at three desktop PCs next.

In our energy tests, the average desktop PC used 102 watt-hours. Acer's Veriton L460 is a compact desktop running an Intel 2.6-GHz Core 2 Duo E4700 processor. PC World's review called this desktop tiny but powerful and a good bet for a business purchase. Here's the win/win: In separate energy tests, the Veriton L460 also earned a pretty nice rep for energy efficiency--it used roughly 48 percent less energy than the average desktop, or 53 watt-hours in total.

It's tricky determining which desktops are really more energy efficient than others because of the different energy needs of each system. The MSI Wind NetTop is a small desktop PC with 512KB of memory and 1GB of RAM. It runs the 1.6GHz Intel Atom 230 processor. With those specs, it's not the most powerful system out there, but if so-called nettops were to be used in large numbers, they could really make a difference in a company's electricity bills and its energy consumption. This desktop uses 39 percent less energy than its peer average of 102 watt-hours, but it does take a little longer than the other PCs we tested to complete the same tasks.

The Alienware Area51 X58 is a high-powered desktop gaming monster that, by its nature, uses a lot of energy. The PC uses Intel's 3.2GHz Core i7 Extreme 965 processor. In total, this PC used 93 percent more watt-hours than the average desktop in our tests. Clearly, this desktop wouldn't move to the top of the green hit parade, no matter how good it is for playing games, which, of course, is Alienware's focus. If you're a hard-core gamer, you're probably not in the market for a green computer anyway.

Next up in our tests: LCD monitors.

Out of the all the 22-inch LCD monitors we tested for energy usage, the Dell G2210t was the most energy efficient--and it was specifically designed by Dell to be that way. PC World's review of the Dell G2210t noted that that this monitor offers three choices--standard, energy smart, and energy smart plus--from which to select the level of brightness and energy consumption you desire. In our energy tests, the G2210t consumed 57 percent less energy than the average of the monitors in its category.

In PC World's review, HP's 22-inch LP2275w was described as a solid, no-frills display for readable documents and vivid images. But when it came to our power consumption comparisons, the LP2275w was hungrier than the other monitors we tested, using 45 percent more energy than the average of the monitors in our sample. If you don't have an opportunity to pick out a more energy-efficient monitor, turn it off when not in use to minimize power consumption.

The next and final group to be tested: laptops.

Ultraportable laptops typically burn less energy than desktop replacement laptops--just because they're smaller and tend to have fewer capabilities. In other words, the simpler the laptop, the less energy it usually needs to function. HP's 3.19-pound EliteBook 2530P laptop features an Intel Core 2 Duo Ultra Low Voltage2 processor. In total, the EliteBook 2530P used 55 percent less energy in our tests than the average of 42 watt-hours, making it look good compared with the other laptops we tested. To learn more about this laptop, read PC World's full review.

Not everyone can afford to give up specialty features that they need in a bigger laptop just for the sake of energy efficiency. Dell's XPS M1730 is a good example. This gaming laptop features an Ageia PhysX engine, which Dell says will help deliver realistic movement and environmental interaction in a game without degrading PC performance. This emphasis on performance--the laptop runs on an Intel Core 2 Duo processor--no doubt contributes to a worse score in our energy tests (that is, a higher energy-consumption number). This powerful laptop with its bright 17-inch screen is ideal for gaming, but PC World's energy test results show that the XPS M1730 used 112 percent more energy than the average laptop. While it's a powerful gaming portable, that performance comes at the expense of energy efficiency.

Acer's Aspire One AOD150 is a member of the new class of small laptops called netbooks. The AOD150 weighs a mere 2.9 pounds, features 2GB of RAM, and is powered by a 1.5-GHz Intel Atom N270 CPU. PC World's full review said this laptop's overall performance was in line with similarly configured netbooks. However, while the AOD150 netbook used 45 percent less energy than the average laptop consumption of 42 watt-hours, it took much longer than the other laptops in this group to complete the same tasks. So ultimately, this netbook is less efficient than more powerful ultralights.

Next: The Energy Meters

Want to do energy testing yourself? The Watts Up? Pro is sold online only for about $130, but if you're interested in getting a less-expensive power meter, P3 International's Kill-a-Watt costs around $25 or so. If you try to calculate how much energy you actually use, remember that most electronic devices sip energy when in hibernation or sleep mode, or even when turned off.

An online electric power pollution converter (prepared by the Texas State Energy Conservation Office) can give you a better idea of how energy use directly affects the environment.

In this short video, Test Center Director Jeff Kuta explains how PC World ran the power consumption tests.

For another great slide show, try 12 Money-Saving, Power-Sipping Green Gadgets for Earth Day.