Sony Bravia KDL-40EX700

We have not reviewed this product but here is CNET's buying advice on Flat-panel TVs. This content was chosen based on the features included with this model of flat-panel tv.

Going "Green" with HDTV

In addition to considering screen size, TV type, and available features also consider ways to conserve energy. Below are a few energy consumption tips for your HDTV:

Turn the TV off when not in use.

Turn on the power-saver mode
Many TVs these days come with a power-saver mode that's designed to cut down the power consumption. Performance of this mode varies from model to model, with the effect sometimes being drastic and other times providing only a slight savings. The only downside is that the power-saver mode usually makes the TV less bright, but we've found that sometimes this has a beneficial effect on the image quality, especially with the room lights turned off, in which case it's a win-win situation.

Turn down the LCD's backlight
Many LCDs give you the ability to control the intensity of the backlight in the TV. By turning down the backlight, you'll lower power consumption, but also make the television less bright. While retail stores love to turn the backlights up all the way for their displays, we find that we get the best image quality when we turn down the backlight significantly.

Control room lighting
Reduction in the intensity of the backlight is going to make the TV less bright, but that can be compensated by controlling the light in your home theater room. While this may be a little overboard just for power consumption, limiting the light in your home theater also goes a long way toward creating the "theater" experience, as well as getting the most out of your TV.

And beyond TV concerns, good-quality blackout shades offer thermal benefits that keep other energy costs low; they keep heat in during the winter and keep it out during the summer.

Watch TV together
Having multiple televisions in a house is more of a norm than a luxury these days, but that also means your power consumption is going to increase as well. You can cut that power consumption by watching with your family or housemates. You might need to make a few compromises on what you watch, but sometimes it's more fun to watch with friends and family.

Don't forget to properly recycle your old model
If donating or repurposing your old TV is not a viable option, CNET encourages households to recycle their electronics. Please explore the following websites to find a recycling center in your area Electronics Take Back Coalition or Earth 911.

HDTVs Earning an Energy Star logo, revised specifications

Beginning November 1, 2008, the EPA and Department of Energy proprietors of the Energy Star logo have established more stringent guidelines for TVs in standby and active modes in an attempt to reduce power consumption. Before you buy your next HDTV, review CNET's comprehensive Quick Guide to TV Power Consumption which includes scores, annual energy cost, wattage used in standby or active modes and much more.

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HDTV source resolutions

There are two main HD resolutions in use today by HD broadcasters and other sources: 1080i and 720p. One is not necessarily better than the other; 1080i has more lines and pixels, but 720p is a progressive-scan format that should deliver a smoother image that stays sharper during motion. Another format is also becoming better known: 1080p, which combines the superior resolution of 1080i with the progressive-scan smoothness of 720p. True 1080p content is extremely scarce, however, and none of the major networks have announced 1080p broadcasts. The term 1080p today appears mostly in reference to the displays' native resolution, not the source.

Source resolution name	Resolution in pixels	HDTV	Progressive scan	Widescreen	Networks/sources
1080p	1,920x1,080	Yes	Yes	Yes	Blu-ray and future HD-DVD players; PlayStation 3
1080i	1,920x1,080	Yes	No	Yes	Includes CBS, NBC, PBS, DiscoveryHD/ Xbox 360
720p	1,280x720	Yes	Yes	Yes	ABC, Fox, ESPNHD
480p	852x480	No	Yes	Yes	Fox wide-screen; progressive-scan DVD players
Regular TV	Up to 480 lines	No	No	No	All

Despite the obvious difference in pixel count, 720p and 1080i both look great. In fact, unless you have a very large television and excellent source material, you'll have a hard time telling the difference between any of the HDTV resolutions. It's especially difficult to tell the difference between 1080i and 1080p sources. The difference between DVD and HDTV should be visible on most HDTVs, but especially on smaller sets, it's not nearly as drastic as the difference between standard TV and HDTV.

For more information on resolution, please read HDTV Resolution Explained

The truth about 1080p

In the last couple of years, there has been a big influx of HDTVs with 1080p native resolution, which typically cost a good deal more than their lower-resolution counterparts. But as we've been saying all along, once you get to high-def, the difference between resolutions becomes much more difficult to appreciate. We've done side-by-side tests between two 50-inch HDTVs, one with 1366x768 resolution (a.k.a. 720p) and the other with 1080p resolution, using the same 1080i and 1080p source material, and it was extremely difficult for us to see any difference. It becomes even more difficult at smaller screen sizes or farther seating distances--say, more than 1.5 times the diagonal measurement of the screen.

We're not telling you to ignore 1080p HDTVs. They technically do deliver more detail, which can enhance the viewing experience for more eagle-eyed viewers. Also, many manufacturers build other picture-quality benefits, such as better contrast and/or color, into their 1080p HDTVs simply because those sets are the high-end models. And given the continuing march of technology, we expect more and more 1080p models to become available at lower and lower prices. Today, however, the premium for 1080p is still pretty steep, and unless you're getting a very large set, say 55 inches or more, we don't recommend basing a buying decision on whether or not the television has 1080p native resolution.

For more information on resolution, please read HDTV Resolution Explained

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Understanding HDMI

HDMI stands for High-Definition Multimedia Interface, and that's a pretty good description of what it is. In layman's terms, HDMI is a type of digital connection that's capable of transmitting high-definition video and high-resolution audio over a single cable. To do the same thing with analog cables, you'd need to connect three component-video cables plus six analog audio cables--that's a whole lot of cable clutter.

HDMI can deliver the best image quality of any of the cable types available today. It can handle high-definition video of up to 1080p resolution at 60 frames per second, which is the most bandwidth-intensive video format currently available. The older PC-based DVI connection offers equivalent quality, but it is rarely available on HDTVs or video components these days. Component video is found on nearly all electronics that output high-def video, and its image quality is slightly lower than HDMI, but it's really difficult for most people to tell the difference. Many viewers are probably familiar with the quality associated with the various standard-definition video cables--namely S-Video, composite (the yellow video cable), and RF--and HDMI provides a potentially huge improvement over all of them. As always, however, the biggest factor in video quality is the source; a low-quality source delivered over HDMI will still look worse than a high-quality source over S-Video.

For audio, HDMI is the reigning king of quality as well. It supports the ability to carry eight channels of 24-bit audio at 192kHz--enough to handle even the highest resolution audio soundtracks such as Dolby TrueHD and DTS-HD Master Audio. The only other connection type that can deliver the same quality are multichannel analog audio cables, but you'd need to run as many as eight separate cables to get the same quality. Digital audio cables--both optical and coaxial--can deliver multichannel audio, but are limited to lower-resolution audio signals.