Instant hot water; tax credit, too

Jennifer McLaughlin never takes a cold shower, thanks to the tankless water heater she had installed in her Vienna home during bathroom renovations in February.

The new shower heads use a lot of water, and the old water heater didn’t have the capacity for the new bathroom, she says.

“Now we have endless hot water,” Mrs. McLaughlin says. “When we have guests in town, everybody can take showers at the same time. Everyone has hot water. If five people take a shower, the fifth person has as much hot water as the first person.”

This year and next, homeowners who install a high-efficiency gas, oil or propane water heater can claim a $300 tax credit on their personal income tax, according to the Energy Policy Act of 2005. Most tankless water heaters qualify.

Tankless water heaters also come in all-electric models.

Unlike many traditional tank water heaters, in which a limited reserve of hot water is maintained, a tankless water heater enables two persons to take hot showers at the same time, says Jason Blackburn, Northeast sales manager at Takagi Industrial Co. USA Inc., based in Pennsauken, N.J. The company, which exclusively manufactures tankless water heaters, is headquartered in Irvine, Calif. Mrs. McLaughlin owns a Takagi unit.

The small unit, the size of a piece of carry-on luggage, usually is mounted on a wall, which enables homeowners to use the space usually needed for the tank for something else, such as a closet.

A series of tubes goes through a heat exchanger that provides the transfer of the flame’s heat to the water, providing continuous heating of water. Custom showers that use high volumes of water might require more than one unit.

“Someone turns on the faucet,” Mr. Blackburn says. “The unit reads there is a flow of water. It will fire. It will take up to 3 to 5 seconds to get up to 122 degrees (Fahrenheit). The water has to move past the flame before it gets hot. You leave the faucet on, and it gives you as much hot water as you want for as long as you want.”

Because heat is applied to the water as necessary, energy is not used to warm “standby” water, as with a traditional tank water heater, Mr. Blackburn says.

An electrical ignition lights the flame, which can be a problem in a power outage.

Heating water accounts for 20 percent or more of a typical household’s annual energy expenditures, according to the U.S. Department of Energy.

With a tankless water heater, an energy savings of 45 percent should appear in the water-heating portion of a gas bill, Mr. Blackburn says. Further, there is a life expectancy of 15 to 20 years for a tankless water heater, sometimes up to twice that of a tank water heater.

Tankless units are more expensive to buy than tank water heaters, but they cost less to operate because they don’t have a standing pilot light, says Daphne Magnuson, director of communications for the American Gas Association.

Because tankless water heaters operate differently from tank water heaters, the gas line coming to the unit usually needs to be larger. Therefore, units can cost two to three times more than a tank water heater, ranging from $800 to $2,200, depending on the type of system. Installation can range from $600 to $1,500.

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