A Realistic Measure of Residential Clothes Dryer Performance
Authored by Christopher Dymond, Northwest Energy Efficiency Alliance; Ryan Firestone, SamDiego Consulting (Paper presented at ACEEE 2018 Summer Study For Buildings)
This paper presents an accurate performance metric for estimating annual energy use of clothes dryers based on multiple laboratory and field testing studies completed in the Northwest and California. The work verifies that heat pump and hybrid heat pump dryers offer a significant savings opportunity, ranging from 300 to 600 kWh/yr (30% to 60%) relative to non-ENERGY STAR electric resistance dryers. Additionally, on average, electric resistance ENERGY STAR dryers use approximately 100 kWh/yr less than non-ENERGY STAR dryers.
The authors have found that current federal performance metrics for residential clothes dryers are unreliable indicators of dryer energy use when subject to typical residential usage. The test procedures do not reflect the range of typical clothing types, load sizes, or dryer settings. Northwest field and laboratory data provided researchers with an understanding of how dryer energy performance is influenced by cycle settings, load sizes, and realistic clothing. This understanding was used to develop an energy consumption metric that reflects realistic dryer usage based on testing with real clothing under a variety of cycle settings and load sizes. The improved energy consumption metric was calibrated to align with four field studies. The resulting metric and typical household savings have been vetted by the Northwest region’s conservation savings estimation body. The authors conducted market research to determine the current market baseline and to evaluate savings from ENERGY STAR electric resistance dryers, hybrid heat pump dryers, and heat pump dryers relative to this baseline.