While ENERGY STAR^®’s draft specification for commercial dishwashers is an important first step, it is still very much a work in progress.

Given the widespread use of this equipment and the potential for large energy and water savings, CEE strongly supports the development of an ENERGY STAR label for this product category. In providing comments about the specification, though, CEE’s Commercial Kitchens Committee is proceeding with caution.

Developing specifications for commercial dishwashers is an involved and complex process because 1) there is no data currently available that differentiates products by energy performance and 2) there is no industry-accepted test procedure for collecting this data.

David Zabrowski of the Food Service Technology Center (FSTC) estimated that it would take his organization at least five years to develop test protocols, collect and analyze data, and apply the data to a labeling program (such as ENERGY STAR). Since the opportunity for energy and water savings through efficient commercial dishwashers is substantial, alternate interim routes are being sought by ENERGY STAR.

Adding to the complexity of this project is the diversity in product categories and technologies. There are dishwashers that sanitize dishes using high-temperature water and there are low-temperature dishwashers that use chemicals for the same purpose.

In addition, some models utilize “dump and fill” technology, which empties the water after a washing cycle and uses more water; tank washers, which use the same water for washing and rinsing, tend to use less water.

The one commonality for all commercial dishwashers is adherence to National Sanitation Foundation (NSF) standards, which include water consumption requirements. Since the energy used for water heating (primary and booster) ranges from 55-95 percent of total energy consumption, dishwasher energy use is closely tied to water consumption.

(Additional energy is consumed for pumps, motors and controls and to maintain water temperature; this is commonly referred to as “idle” energy.)

ENERGY STAR’s draft specification for commercial dishwashers uses rinse water consumption as a proxy for energy usage. The Commercial Kitchens Committee acknowledged that the water/energy correlation may apply in many cases but concluded that there is no direct evidence to support that water consumption is a reliable metric for energy usage in all the varying product types.

FSTC research has shown that, in some cases, models that use less water can consume more energy and vice versa.

The Committee’s comments to ENERGY STAR were supported by 11 CEE members, GasNetworks (a consortium of gas utilities that includes five CEE members) and the City of Toronto Water Efficiency Group, a water agency participating in the Commercial Kitchens Initiative.

The Committee recommended that EPA conduct additional research to demonstrate that rinse water consumption is a reliable proxy for energy consumption, resulting in quantifiable energy savings, for specific types of commercial dishwashers.

CEE is willing to support an ENERGY STAR program using rinse water consumption as an “interim labeling criteria” based on this information.

“If, for some reason, it is not possible to reliably use rinse water consumption as a proxy for energy consumption, then the Committee recommends that EPA expedite efforts to develop a credible, industry-accepted, energy test procedure and to collect performance data for analysis,” said CEE’s Ted Jones, who manages the Commercial Kitchens Initiative.

“In moving forward, we believe it would be better for EPA to either wait until a direct energy test can be developed or to narrow the scope of products covered so that the future addition of a direct energy criterion will minimize any market confusion.”

If a revised test procedure is deemed to be the best solution, the Committee recommended that it include pre-heat energy, idle energy, and all energy consumed during the wash and rinse cycles.

Another option for a specification is to measure the idle energy usage of the dishwasher and determine how it correlates to the overall energy usage. An American Society for Testing and Materials (ASTM) test procedure can provide this data.

Zabrowski estimated that testing, collecting and analyzing the data would take approximately 6-9 months, adding that it would probably not be difficult for manufacturers to provide the information. Rachel Schmeltz of EPA indicated interest in exploring this option.

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