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Time to go Tankless? On Demand Water Heaters Keep Energy Costs in Check


NATIONAL REPORT—If you wanted just one hot cup of coffee, would you keep the kettle burning 24 hours a day? Does not make much sense, does it? In a way, however, that is what most hotel and restaurant operators are doing every day of the year with their hot water supply—keeping it hot even when guests and customers do not need it.

“When providing 200 rooms with hot water, you can only imagine how much energy is wasted,” says Francis Serrano, marketing coordinator for Noritz America Corp., a maker of tankless water heaters in Lake Forest, Calif.

Outside of the United States, throughout Europe and Asia, tankless water heaters have been common for years. These continuous flow, on demand types of heaters offer substantial savings in energy—from 20 percent to 40 percent or more in fuel costs, experts say.

Natural gas is the standard fuel for tankless water heaters. Less energy is consumed because water is heated only when it is desired. Hot water never runs out because it is heated instantly within a heat exchanger. They are portable, require much less space than traditional hot water tanks, last up to two to three times longer, reduce nitrous oxide emissions and require no pilot light. They will not burst and cause water damage. Tankless heaters include on-board computers to ensure maximum efficiency and can be set to precise temperatures (plus or minus 2 degrees).

Tank heaters are available in various sizes. Noritz’ largest commercial model heats 13.2 gallons a minute. Assuming five guests were taking a shower simultaneously while using about 2 gallons a minute, one heater could potentially take care of the needs of six to seven guestrooms.

Heaters Grouped Together

How can these types of heaters accommodate a large hotel? They can be joined together in one system. In such a configuration, a system controller manages the water heating and flow. Serrano says up to 24 of his company’s heaters can be used together. The controller alternates heating between the heaters to extend heater life.

“If one heater fails in a multiple unit configuration, the system continues on,” says Fred Hoffman, commercial accounts manager for Peachtree City, Ga.-based Rinnai, another maker of tankless water heaters.

Hoffman says there is no limit to the number of units his company can join together. For every five of Rinnai’s units, a controller is needed. In some configurations, a holding or storage tank can be used. Tankless heaters mounted indoors require venting; those mounted outdoors do not. A plumber is required to install and remove the heaters. It can take as little as 40 minutes to replace a heater.

Hoffman says that for hotel owners considering new construction, the cost of tankless heaters is a wash. For existing properties, initial costs will be more because of the retrofit steps and new gas line required.

“A tankless water heater can pay for itself in three to five years,” Serrano says.

In addition to saving energy, tankless water heaters do not cause the waste problem that tank heaters create.

“They are not throwaway heaters,” Hoffman says. “You just replace parts.”

In regard to preventive maintenance, each unit should be cleaned of scale buildup every six months. As with a traditional hot water tank, water hardness will determine the rate of scale accumulation. When something does go wrong with a unit, each heater’s on-board computer will display a code pertaining to the specific problem.

Hoffman says the Hilton Garden Inn and Country Inn & Suites by Carlson—both in Effingham, Ill.—are currently using a Rinnai system that includes multiple tankless water heaters. Properties that have implemented Noritz systems include the MiraMonte Resort & Spa in Indian Wells, Calif. and the Miyako Hotel in Los Angeles.

Be sure to check with your local utility company to learn whether or not rebates or incentives are available.

For more information, go to Noritz America Corp., Rinnai or Rheem.

Glenn Hasek can be reached at greenlodgingnews@aol.com.