Tankless water heaters are getting a lot of buzz these days. After all, they can reduce a household's water-heating energy use by 20-50%. And that's no chump change: Water heating counts for about a third of a house's total energy usage.

Instead of chewing up power to keep 30 gallons of water hot all day (or 50, or 80, depending on the size of your tank), tankless heaters only warm up water when you need it. And since they work on demand, you can run shower after shower and never worry about having the hot water run out right after you've sudsed your hair. Plus they take up significantly less room than a tank. And if they've worked for Europeans for decades, shouldn't they work just as well for those of us across the pond?

It depends.

If energy efficiency is your top priority, a tankless heater is probably the way to go, since they do consume significantly less energy than a storage tank.

If cost plays more of a role in your calculations, you might need to think about it. Tankless heaters cost more than storage tanks. And some homes will need to upgrade their gas lines and install venting systems in order to use the systems, which further pushes back the break-even point on your initial investment.

In theory, tankless heaters — like solar power systems — should save you money over the course of their lifetimes, especially since they can last five to 10 years longer than a tank heater. But depending on how much work you need to do upfront, that might not turn out to be the case. (When you're doing your calculations, though, keep in mind that many tankless water heaters qualify for a federal $300 energy efficiency tax credit.)

The bottom line: Do your homework, and make the choice that fits your household's priorities. And if you don't need a new water heater immediately, give the tankless system a look when your time comes. The technology is evolving rapidly, now that energy costs are expected to rise and folks are becoming more conscious of their carbon footprints. By the time you're in the market for a heater, it could be just the thing.

To learn more:

— How Stuff Works has a great summary that will help you evaluate whether a tankless heater is for you.

  —The U.S. Department of Energy's Energy Efficiency and Renewable Energy website also has detailed information.

  —GetWithGreen.com shows you how to calculate the return on your investment.

  —The comments on this Re-Nest article offer a lot of real-world insights from readers about the pros and cons of using tankless heaters.

Photo credit: omiksemaj