Energy Adviser: Pros and cons of tankless water heaters

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Ah, hot water.

There’s nothing better than a long, hot shower after a day in the cold outdoors. But heating water, whether it’s for washing clothes and dishes or for that steamy shower, is the second-most expensive energy use in a home.

In a home with electric heat, about 16 percent of total household energy consumption goes to hot water, with 58 percent going toward heating interior spaces. Depending on your own home, you may be ready to cut your electric bill by investing in a high-efficiency water heater or by switching to a “tankless” unit that heats water on demand.

According to the Clark Public Utilities’ free home energy calculator on its website, two people living in a 1,200-square-foot, two-bedroom home will pay about $200 a year for hot water. For a family of four living in a 2,000-square-foot, three-bedroom house, the cost jumps to $324 a year, or $27 a month. High-efficiency tank water heaters that use better insulation can cut your hot water costs by 10 percent or more.

Going tankless

On demand, tankless water heaters that use electricity to instantly heat water may offer even more savings because they don’t have to keep a standby tank of water continuously hot.

“What you save in energy costs with either a high-efficiency traditional water heater or a tankless unit really depends on how you use hot water,” said Tony Sarkinen, owner of Sarkinen Plumbing in Vancouver. “We try to find out as much as we can about our customers before we sell them a tankless unit or any water heater for that matter.”

Sarkinen’s questions to consider include:

• How long are your showers? If you invest in a new high-efficiency (but traditional) water heater, the size of your heating tank is important. You don’t want to run out of water .

• If you go tankless, how much patience do you have when waiting for hot water to reach the shower head or faucet? It will take a few seconds for a tankless heating unit to fire up and deliver the “instant” hot water.

• What kind of water pressure are you comfortable with, because a tankless unit may not deliver the pressure that you are accustomed to.

Your answers will determine what kind of unit Sarkinen and other plumbing installers will recommend for you.

“I bring up these issues because a tankless, on-demand water heater comes with some trade-offs,” Sarkinen said. “There’s also the cost, which can be up to four or five times greater than your traditional water heater, which usually runs about $700.”

Ideal situations

For some situations, a tankless unit may be ideal. A vacation cabin at the beach for example, where there’s no reason to keep water hot when no one is there.

Some homeowners like tankless technology because of the lower energy costs and the fact that they never run out of hot water. As well, a tankless means less risk of water damage. A storage tank heater can leak or rupture in as few as 10 years and requires a metal pan to collect leakage if installed in an interior closet or attic space. The only risk of water damage from a tankless unit is from a pipe or pipefitting failure.Energy Adviser is written by Clark Public Utilities. Send questions to energyadviser@clarkpud.com or to Energy Adviser, c/o Clark Public Utilities, P.O. Box 8900, Vancouver, WA 98668.