See a holiday deal on laptop that you can't pass up? Before you pull out your credit card, just remember that with many purchases, you’ve got two price tags: The one you pay at the register, and the one that you slowly pay over time through your electricity and gas bills.

That second price tag’s the one environmental nonprofit National Resources Defense Council wants to help you reduce this holiday season — while also saving the environment, of course — with a new green website called TopTenUSA. The intent of the site is simple: To let you see at a glance the top 10 most energy-efficient items in any category!

Because while a low price tag might save you cash in 2010, it could really cost you in 2011. NRDC’s Dale Bryk explains how the energy-efficiency savings can add up — or not — depending on your shopping choices:

TopTenUSA estimates a consumer can save two-thirds of the $440 to $650 a year he or she now spends powering old appliances and electronics by replacing them with TopTen models, rather than non-ranked ones.

That kind of cash — $300 to $400 or more every year — is nothing to be sneezed at. The same goes for cars: Trading in an old model with simply average mileage for a TopTen-er will save approximately 130 gallons of gas each year. That’s a lot of money in the bank and clean air in our atmosphere.

Interestingly, NRDC’s site isn’t eco-judgmental. There are no admonitions against SUVs or extra large refrigerators; both categories simply list the top 10 energy-efficient items. Looking for the biggest TV with the biggest energy savings? Samsung’s 46-inch, LED-backlit TV tops the “Large TVs” category. Need an extra freezer because your eyes are bigger than your stomach? Whirlpool makes four of NRDC’s top 10.

Unlike my own blog, TopTenUSA won’t repeat over and over that you’d be better off reducing and reusing instead of buying new. In fact, all listed items on TopTenUSA come with handy shopping links, in case you want to keep your holiday shopping energy efficient by completing your purchases with a few quick clicks.

Of course, TopTenUSA won’t answer all your consumer questions. NRDC’s site’s really only does one thing: Name the top 10 most energy-efficient products. That’s it. Curious if your energy-efficient laptop could let you cut down on an electronic because its speakers are good enough to double as your stereo? Anxious about how well your energy-efficient dishwasher cleans without a water-wasting pre-rinse? Skeptical about your TV company’s e-waste collection policies? Concerned your new monitor might contain PVC or other potentially dangerous materials? You’ll need to do your own research to find answers to those questions.

If the thought of doing all that extra research makes you want to give up holiday shopping for electronics altogether, congratulations! You’ve just saved yourself a whole bunch of money — unless your refrigerator is really, really old and sucking up a lot of energy, in which case I suggest making a New Year’s Resolution to do some research. Otherwise, enjoy the extra cash in the new year!

TopTenUSA makes energy-efficient shopping easy
NRDC's new site ranks the top 10 most energy-efficient products in many consumer categories -- and lets you buy them with a few quick clicks.