Fridge Icemakers Devour Kilowatts: NIST

The amount of energy they use and what most of that energy is not used for are surprising. Refrigerators account for 8 percent of total energy use by 111 million U.S. households, according to DOE, which helped to fund this research.

The energy consumed by refrigerators' icemakers and what most of that energy is not used for are both surprising. In tests of four different types of new refrigerators, researchers from the Commerce Department's National Institute of Standards and Technology discovered that icemakers increased rated energy consumption by 12 to 20 percent. About three-fourths of that additional energy cost is due to the electric heaters used to release the ice bits from the molds.

Thus, "there are substantial opportunities for efficiency improvements merely by optimizing the operations of the heaters associated with the ice makers" or by introducing a more efficient alternative technology, NIST mechanical engineer David Yashar and guest researcher Ki-Jung Park assert.

Refrigerators account for 8 percent of the total energy used by 111 million U.S. households, according to the Department of Energy, which helped to fund the research. Icemakers' energy consumption is not factored into federal minimum efficiency standards for refrigerators or in the voluntary Energy Star program, which requires energy usage to be significantly lower than the regulatory limit. DOE plans to raise the minimum efficiency standard by 25 percent from its current level starting in 2014 and will include icemakers' energy us in the regulatory test. Because no widely accepted test for icemakers was available when it announced these changes, DOE intends to add 84 kilowatt hours to the energy efficiency rating of every refrigerator equipped with an icemaker, Yashar said.

When a reliable test is available, DOE will use actual icemaker test results in the efficiency ratings. Yashar and Park evaluated several ways to measure the energy consumption, testing different refrigerators with a variety of icemaking technologies and measuring energy consumption during ice production and while the icemakers weren't operating.

More research and evaluation of measurement techniques will be done, and other laboratories will test icemakers and compare results for similar units.