Residential Clothes Dryer Summit: Moving Forward Together

Over the past two years, energy efficiency advocates and program administrators have funded technical

research on clothes dryer energy efficiency. The table below provides a summary of past, current, and

planned research:

Research Area Research Entity Description Link to Results

Dryer Modification (2012-2013)

The California Statewide Codes and Standards Team, including Pacific Gas & Electric Company (PG&E), Southern California Edison (SCE), San Diego Gas and Electric (SDG&E), and Southern California Gas Company

PG&E’s technical consultant, Ecova, modified two conventional dryers to assess the impact on energy consumption. Modifications included the following:

Adding insulation;

Adding a heat exchanger; and,

Re-routing the air flow;

KEY FINDINGS: A modified conventional dryer can reduce energy consumption by 20%.

Link1

Field Study (2011-2012)

Northwest Energy Efficiency Alliance (NEEA)

NEEA conducted a field study on consumer clothes dryer usage. The study collected data from 50 households in four states.

KEY FINDINGS: The study provides data on how consumers in the Northwest use their dryers, the energy consumption of clothes dryers in the field, remaining moisture content of clothes entering the dryers, dryer cycle times, and the size and nature of the clothes loads being dried. Data indicates the number of dryer loads per year and energy use per load is higher than DOE and EPA assumptions.

Link2 Link3

1 http://www.energystar.gov

Field Study (2013-20??)

US Department of Energy (DOE)

The Florida Solar Energy Center (FSEC) is currently monitoring the energy consumption of several homes in Florida through DOE’s Building America program. FSEC is measuring the energy consumption of clothes dryers and HVAC systems and replacing equipment with higher efficiency models as part of a phased, deep energy retrofit project.

Link4

Field Study (20??-2013)

The California Investor Owned Utilities (IOUs) Statewide Codes and Standards Team

The California IOUs’ technical consultant, Heschong Mahone Group (HMG), conducted field testing of commercial clothes dryers in California and plans to release a proposal for mandatory commercial clothes dryer standards as part of the California Title 20 appliance standards process.

Laboratory Testing (2011-2012)

Collaborative Labeling and Appliance Standards Program (CLASP)

CLASP’s technical consultant, Ecova, compared the energy consumption and performance of North American conventional dryers and that of European heat pump dryers. Ecova also assessed the impact of test cloth that more closely resembles the type of laundry dried in the real world.

KEY FINDINGS: Heat pump dryers use 50 to 60% less energy than the average conventional dryer. Drying laundry that more closely resembles the real world significantly increases dryer energy consumption and drying time.

Link5

2 http://www.energystar.gov

3

http://www.regulations.gov/contentStreamer?objectId=0900006481235b48&disposition=attachment&contentType=pdf 4 http://www.ba-pirc.org/overview/index.htm

5 http://www.clasponline.org/en/Resources/Resources/SLHeadlines/SEDI-Transforms-North-American-Market-for-

Super-Efficient-Dryers

Laboratory Testing (2009-2011)

Natural Resources Defense Council (NRDC)

NRDC’s technical consultant, Ecova, assessed the impact of test load composition, fuel type, and automatic termination on the energy consumption of dryers.

KEY FINDINGS: The composition of laundry significantly increases dryer energy consumption. In addition, a correctly functioning automatic termination feature substantively reduces dryer energy consumption. Furthermore, natural gas dryers have significantly lower source energy and greenhouse emissions than electric dryers.

Link6

Laboratory Testing (2012-2013)

Northwest Energy Efficiency Alliance (NEEA)

NEEA’s technical consultant, Ecova, tested several dryers with a modified test procedure that more closely aligned with the type of drying conditions identified in the NEEA field study above. Ecova plans to conduct additional testing on two European heat pump dryers. One uses supplementary electric resistance heat and the other uses a variable speed compressor, both of which reduce drying time.

KEY FINDINGS: Each dryer responded differently to the NEEA test procedure, indicating that it may be difficult to predict how dryers perform in the real world using results from the DOE federal test procedure.

Link7

6 http://www.appliance-standards.org/sites/default/files/NRDC_Ecova_dryer_study_0.PDF

7 http://www.energystar.gov/