Do Savings Come Out in the Wash? Study Pinpoints Laundry Energy Waste
October 7, 2011 - The age-old chore of laundering clothes is undergoing a technology revolution as major manufacturers develop new smart grid washers and dryers. Now, a study conducted by environmental and energy research firm Cadmus Group reveals insights into how these manufacturers—and consumers—can minimize energy waste in laundering.
During the study, Cadmus engineers tracked the energy consumption of 115 household laundry systems in southern California and the San Francisco Bay Area. The team deployed Onset HOBO energy monitoring systems to collect data at each site, measuring volumetric flow through the hot water hose serving the clothes washer, the temperature of the hot water entering the clothes washer, and the electricity consumed by the washer and electric dryer.
The collected data unearthed findings that can help inform manufacturers as they seek ways to fine-tune new “smart” washers and dryers, says David Korn, a principal at Cadmus Group and co-author of the study.
“Contrary to conventional wisdom, the energy use of the washer is not an issue. Hot water used in washing clothes is moderately important, but we found that households only use hot water about 13% of the time,” Korn says. “The majority of the energy consumed and potential savings arise in reduced operation of the clothes dryer, not the washer.”
As a result, washing machines should be set at high rates during the spin cycle to remove as much moisture as possible from the clothes. This reduces the amount of time the clothes must spend in the more energy-intensive dryer.
Front load, or horizontal axis tumbling washers, have become increasingly popular among the environmentally-conscious because they use less water than top load or vertical axis washers. But front loaders often shake and create noise in the spin cycle, causing consumers to set them at a slower spin speed to avoid the commotion. This leaves the clothes wetter than if the spin speed were high, and negates much of the energy benefit of using a more efficient appliance, Korn says.
“These findings can serve as a bridge to help manufacturers better understand changes needed to make smart grid washers and dryers more effective,” Korn concludes. “I hope they will also help the industry understand that consumers need to be educated about how to use the spin cycle.”
The full report, “Do the Savings Come Out in the Wash? A Large Scale Study of In-Situ Residential Laundry Systems”, can be ACCESSED HERE (opens PDF).