Are you harboring an energy hog without even knowing it? Sure, all of the appliances and gadgets in your house — your television, DVD player, set-top box, toaster, game console and more — are constantly sucking energy. But some are worse than others.

We've rounded up five of the worst offenders in terms of energy efficiency. Now, there's no question that each of the products named here does wonderful things, making them unique among their peers. The thing they have in common, however, is the task they perform best: burning through energy. Like, a lot.

1. 65-inch Panasonic Viera TH-65VX100U

Energy consumption: 575 watts (in operation)

Why it sucks (energy, that is): A plasma TV is already a losing proposition when it comes to being energy efficient. An LCD or LED display will beat a plasma set every time, using half or even a third of the power, though you get a richer contrast on a plasma screen. Panasonic has made great strides reducing the energy costs of plasma TVs making it the brand to watch, but plasma isn't on par with its peers just yet. The situation is further exacerbated by legislation like the kind laying down in California, which could ban the sales of any set in January 2011 that doesn't meet a level of power consumption that's honestly out of reach for most plasma sets right now (though screens larger than 58 inches diagonal, like this Panasonic, will be exempt). Translation: the country may not wait for plasma TVs to get where they need to be.

Green tips: Every other television out there — from LCDs and LEDs to projection TVs — will use less energy. Going for a different set is really your only option here.

2. Origin Genesis Gaming PC

Energy consumption: 585 watts (in operation)

Why it sucks: Gaming PCs have to be powerful, and Origin certainly lives up to that expectation. There's one area where it's machines fall behind the competition, though: power consumption. CNET ran a test pitting the Genesis against similar gaming PCs — not only was it the most expensive in terms of energy cost, but it nearly doubled another machine.

Green tips: You probably have your PC plugged into a power strip, right? Well, when you're all done, shut it off to help combat standby power. Other than that, either use your machine less (a huge bummer), invest in different parts to lower its power consumption (a lot of work) or buy a new machine altogether (a lot of dough). Another suggestion? Laptop.

3. Dyson DC23 Canister Vacuum

Energy consumption: 1,400 watts (while on)

Why it sucks: You know Dyson. The company makes solid vacuums and crazy… other things. It also cranks out one of the most powerful vacs you can buy, the DC23 canister vacuum. With 220 airwatts of suction, it'll suck up even the most entrenched grime, but at 1,400 watts of electricity it'll hoover up your spare change, too.

Green tips: It's easy to become reliant on a vacuum, but don't forget about brooms and mops for surfaces such as hardwood and tile. Or, hey, maybe buy a vacuum that doesn't require a nuclear reactor to run!

4. Xbox 360 Elite

Energy consumption: 165 watts (while playing a game)

Why it sucks: When the original version of the Xbox 360 hit the scene, it was just barely eclipsed by the PlayStation 3 in terms of power consumption, and the latter system took the heat. Now, three years later, the 360 enjoys a motherboard revision with a smaller, more efficient 65nm processor, and uses less power than ever before. Unfortunately, it now enjoys the dubious honor of being the console world's energy hog, as Sony really cut back the power needs of the PlayStation 3 with its "Slim" revision.

Green tips: Honestly? Consider a Wii. It sips power. Of course, that means you'll also have to consider playing Wii games, so… you know.

5. Life Fitness Platinum Treadmill

Energy consumption: 2,400 watts* (in use)

Why it sucks: For those who use one often, a treadmill can cause surprising hikes in electricity bills. Let's crunch some quick numbers using the Department of Energy's handy formula. Let's say you use your treadmill for an hour daily, and you pay $0.09 per kilowatt hour of energy (the national average in January, 2010). You'd be looking at an annual bill of $78.84 for the treadmill alone. That's $6.57 monthly.

Green tips: The guiding principle when buying a treadmill is it'll use 750-1,000 watts per one horsepower. Going for a lower horsepower machine will help keep your costs down. There's another thing you can do, though — run outside. It's free!

*We had to estimate this one, though we found a spec sheet that said the Life Fitness treadmill required a 120 voltage line rated for 20 amps. We'd take this figure as a minimum, though, as the formula in "green tips" would have the Platinum using more.