The next time you're standing under the hot shower, consider this: 14 cents out of every dollar you spend on your home's energy bills goes toward water heating. That amounts to about $300 dollars a year on average. But if your water heater is ready for a replacement (13 years is the typical life expectancy) upgrading to an energy-efficient technology could cut your water heating costs in half, according to a new study by the American Council for an Energy-Efficient Economy.

The study, titled "Emerging Hot Water Technologies and Practices for Energy Efficiency as of 2011," examined 16 water heaters in all, including heat pump water heaters, high-efficiency gas water heaters, and tankless water heaters. The sheer volume of choices now on the market was among the key findings. “The technologies we evaluated represent a sea change in the way we think about heating water,” said Harvey Sachs, lead author and ACEEE Senior Fellow, in a statement. “Consumers can now choose among many sophisticated tank, tankless, and solar water heating systems to meet their needs.”

Consumer Reports' latest tests of water heaters reached many of the same conclusions about the newest technologies. In particular, we found great potential for energy savings from units that use a heat pump to draw heat from the air to heat water. One tested model by A.O Smith (pictured) delivered an annual savings of 59 percent over conventional electric water heaters. Solar water heaters also showed a lot of potential in our tests, with one model by Eagle Sun delivering an average 55 percent savings.

Regardless of the technology you choose, it's important to get a model with a tank that's big enough for your hot water needs. Most water heaters are sold on the basis of how many gallons they hold. If you're considering a tankless water heater, check the gallons-per-minute rating, which tells you how much hot water the heater can deliver during a set period. For more detailed advice see our complete buying guide to water heaters and watch this video on how we test.