CEE’s Gas Committee is moving forward in its exploration of high-efficiency specifications for traditional tank-type water heaters and in the development of field-testing methods for tankless water heaters.

The committee is also working with the Gas Appliance Manufacturers Association (GAMA) in an effort to obtain shipment data on energy-efficient units.

Tank-type heaters
For the tank-type heaters, CEE is building on work undertaken by the California Energy Commission, which had formulated a two-tier specification as part of its Super-Efficient Gas Water Heater Appliance Initiative.

The CEC initiative was aiming to create a market for water heaters that are 30 percent more efficient than models currently available on the market.

Manufacturers have stated that production of more efficient water heaters is technically feasible, but the question is whether the gas savings can justify the incremental cost for consumers. To help answer this important question, CEE is encouraging and coordinating member input on cost/benefit analyses of higher-efficiency units.

Another uncertainty is the cost effectiveness of running a program that provides incentives for this type of equipment.

At the same time, CEE’s Gas Committee is seeking input from manufacturers. Preliminary feedback indicates interest in producing the units, along with concerns about incremental cost.

Tankless units
Tankless or “on-demand” water heaters appear to provide significant savings in certain applications but no formal study has been made to date. To calculate the actual savings and determine the best uses for this technology, CEE is developing general guidelines for conducting field tests of this equipment.

More than 90 percent of current residential water heaters are traditional tank-type models, which heat and store large quantities of water (typically 50 gallons or more) for later use.

By keeping water hot for indefinite periods of time, this type of water heater wastes energy; according to CEC research, these standby losses can reach 15-20 percent.

Tankless models heat water only as needed and can be much more efficient because standby losses are significantly reduced. Anecdotal evidence tells us that tankless water heaters, used in about 2 percent of American homes, are more cost effective in one- to two-person households where the demand for hot water is less.

There are, however, concerns about the unlimited amounts of hot water that could potentially be available through the endless hot water tankless units.

It is possible that this offer could lead to even greater water and energy consumption, especially in larger households. To date, no field tests have been conducted to determine whether consumer behavior does change with tankless units.

“Our members need to know whether the savings promised by tankless water heaters will be realized,” said CEE Senior Program Manager Kara Rodgers. “By working together to create consistent testing methods, our members can compare the results across North America and gain more robust results than we could by working individually.”

ASHRAE and Lawrence Berkeley National Laboratory are in the process of developing technical guidelines for the field tests. CEE is working on a consumer questionnaire that would address usage habits and product satisfaction.

Field tests would be administered to homes retrofitting with a tankless system. Monitors would determine energy usage before and after the retrofit.

Shipment data
In past meetings with manufacturers, efficiency program administrators have explained the importance of shipment data of efficient equipment. The data can establish baseline levels of efficiency to help in planning programs.

GAMA is physically capable of collecting the data and manufacturers are generally supportive of any action that would lead to greater sales of energy-efficient equipment. CEE’s ongoing negotiations with GAMA are aimed at reaching an agreement in the release of this information.

DOE proposal
On May 2, DOE released draft criteria for ENERGY STAR residential water heaters. CEE is working with interested members to develop comments on the many aspects of this new proposal.

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