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Tankless water heaters raise temperatures, debate

| Sunday, Feb. 12, 2012

Jim Dinucci has an item in his home that he says he "wouldn't be without," but adds he wouldn't "necessarily recommend one to others."

They are called "a slam dunk" for new construction, but get a warning for "case-by-base investigation" in retrofit projects.

They have the reputation of being hip in their newness, but Dave Dzombak from Carnegie Mellon University says he grew up in Latrobe with an old model in the '50s and believes it dated back to the '20s.

They are ventless water heaters, which do not store and heat water in a tank, rather warming it as it is needed. They are liked by "green people" who want to use less energy for heating water, says Doug Breier from A.O. Smith Water Heater in the Strip District.

But one of their bigger benefits comes after they are installed and a steady supply of hot water makes conservation-mindedness almost secondary, says Trey Hoffman from Rinnai America Corp., a producer of tankless heaters headquartered in Georgia in this country.

The difference between a tankless heater and a storage unit is in the way it prepares hot water. A storage unit will keep warm 40 or 50 gallons of water, requiring a steady supply of gas or fuel to do the job. In a tankless system, water is brought to a desired temperature as it passes through a heating unit. That temperature is chosen by the owner, but the initial discharge of water would be cooler because the heating process is in its first steps.

After that, though, the temperature is constant.

Tankless heaters tend to raise debate about as easily as they raise temperatures.

Dinucci is the owner of an eponymous plumbing firm and has had a tankless heater in his Shaler home for 25 years.

But he says they normally cost three times what a storage heater costs to install, generally require more time to do that job and can be less than satisfactory if a homeowner underestimates needs. A large family in which multiple showers are common would need a more powerful unit, experts remind.

"If you are satisfied with what you have, stay with a storage unit," he says.

He and other installers such as Breier and Mike Barth from Ben Franklin Plumbing in Greensburg tend to agree tankless jobs are about three times the cost of storage units, or $2,500. The price can be higher, if installation difficulties arise, they say.

Heaters generally are more expensive and the installation process generally requires mounting and venting work that boost the bill, they say. That work also can make the job take several days as opposed to the virtually immediate replacement of a storage unit,

"There is a lot of hype out there about them," Breier says, but he and Barth see interest from only about 10 percent of their customers.

Hoffman agrees to the figure nationally, but says it is growing. Some experts believe there is more interest in warmer parts of the country because the heating process can be even more efficient there.

Consumers Union, publisher of Consumer Reports, says the larger cost of tankless jobs makes their payback time longer. That delay makes installation questionable for any person not planning a long stay in their home, the organization's report suggests.

"If you spend $2,500 and you save $10 on your gas bill a month. how long does it take for the heater to pay for itself," Breier says.

But Ren Anderson from the National Renewable Energy Lab of the federal Department of Energy says use of tankless heaters is in line with the department's desire to cut energy use by 50 percent.

He admits installation can raise the costs of such projects, but says those costs are less in new construction because venting and placement are part of the original work, not a matter of revision.

He calls them a "slam dunk" for those jobs.

Erin Connealy from the department's Office of Energy Efficiency and Renewable Energy says state and commercial rebate programs also can help reduce those costs. Such programs are listed at, she says.

Tommy Olsen, a marketing manager for tankless and specialty products for Rheem Water Heating, also in Georgia, contends prices are coming down for installation. He suggests they would be less than double the price of a storage unit, making the payback easier to come by.

Olsen, Hoffman and Dinucci all insist investigation and knowledge of a household's needs are vital for any consideration of a tankless installation. Dinucci, for instance, brings up the issue of heat "depletion" which could take place with a large family that might have several people taking a shower at the same time. That would challenge the amount of water being heated by a tankless unit in the way it would test the supply of water held in a storage device.

Hoffman calls the matter of "sizing" one of the biggest issues.

"You have to understand house size, family size, so we you can say 'We need a unit that is this big'," he says.

For instance, a house of two or three people probably can get away with a 120,000 BTU unit, but if multiple demands arise, a 199,000 BTU system might be necessary. The extra heating ability is what provides warmth to many sources.

Such efficiency is the biggest issue, says Dzombak, who is a professor of civil engineering and director of the Steinbrenner Institute for Environmental Education and Research at Carnegie Mellon.

The efficiency issue also has led Rheem to develop its XR90 storage water heater, which holds 90 gallons of water in a unit not much larger than a 50-gallon unit.

That system, Olsen says, can provide service for multi-user homes with no one shouting , "Hey, you are using up all the hot water," he says.

The whole issue becomes one of education, he says. A homeowner needs to determine the needs to the house and determine whether ventless or storage units are more practical.

For instance, Hoffman says, a person taking a shower uses about 2.5 gallons a minute. A long shower can come close to using a tank of hot water. A storage system can be taken to the brink in such a setting.

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