When it comes to your gas and electric bill-- it may surprise you to learn up to 30 per cent of your money goes to heating your water.

One way to save might be to invest in a tankless water heater. You may never have heard of them but they're big in Europe and Asia. But can they save you money here?

Shari Dipaola's two teenage sons take a lot of hot showers, which she knows can add up.

"They're always in the shower," she admitted. "Jarred comes back from work, Alex comes home from work, they're in the shower."

Some manufacturers of tankless water heaters claim to cut your energy costs in half.

Consumer Reports tested both tankless and regular water heaters to find out.

Tankless water heaters are more energy efficient because they don't store hot water.

They heat water when needed. Testers, with the help of an outside lab, assessed the water heaters for both energy use and the cost to operate. Tankless heaters do have their drawbacks.

"Some people think that tankless water heaters provide instantly hot water to the faucet. That is not the case," cautioned Gian Trotta of Consumer Reports' testing lab.

Another issue -- if you only need a trickle of water, say for shaving, the tankless heaters

burner may not ignite and all you'll get is cold water. Along with a higher price tag, tankless water heaters can be a lot more expensive to install. But tankless systems can last twice as long -- or more -- compared with regular water heaters.

According to Consumer Reports' tests, tankless heaters could save you around $70 to $80 per year on your energy bills.

"But their high cost means it could take you up to 22 years just to break even, and that's not necessarily a big money saver," said Trotta.

If using less energy is important to you from a conservation perspective, getting a tankless water heater may be worth the expense.

There are $60 million worth of incentives available for homeowners to make their houses more energy efficient from furnaces, heat pumps, and fireplaces, to woodstoves, thermostats and tankless water heaters.

The higher your efficiency the greater the rebate it can be hundreds of dollars.

One final important point the cost of installation can vary widely based on where the tankless system is going to be placed in your home. So before you commit yourself get some firm estimates and do the math.

With a report from CTV British Columbia's Chris Olsen