Heat-Pump Clothes Dryers Really Work, Study Confirms
For the past two decades, there has been little improvement in energy efficiency for North
American clothes dryers. Recent innovations in clothes drying technology offer new
opportunities for energy savings. One innovation in particular has substantial savings potential:
clothes dryers utilizing heat pump technology. This technology has already made significant
market gains in Europe and Australia, but is not yet sold in North America. Manufacturers are
looking to bring heat pump clothes dryers to North America in the near future.
The successful market introduction of this new, highly efficient technology will require support
from energy efficiency program providers and governments in North America through labeling,
promotion, and incentives. Programs and governments must have high-quality data on the
energy savings that can be expected from heat pump technology before providing this support.
Our study compares the energy consumption of currently available European heat pump dryers
to North American conventional electric dryers to better understand the potential for energy
savings if this technology were introduced into North America.
To develop these data, Ecova procured four European models and three conventional North
American models spanning a wide range of sizes, prices, features, and manufacturers. To
compare dryer efficiency and performance, each dryer was subjected to the same tests: the
current (2005) US Department of Energy (DOE) clothes dryer test procedure and the proposed
2011 DOE test procedure that Ecova modified to include automatic termination in anticipation of
a revised DOE test procedure. In 2013, after the testing and analysis was completed, the DOE
did indeed propose a revised test procedure. This test procedure is very similar to the
anticipated DOE test procedure that was used in this work. The 2011 DOE test procedure, with
automatic termination, was also repeated with several alternative test laundry loads that more
closely resembles real-world clothing than does the DOE-defined test load.
Key findings include:
• European heat pump dryers use only 40-50% as much energy as North American
conventional dryers to dry the same amount of laundry;
• European heat pump dryers took twice as long to dry a load of laundry as North
American conventional dryers;
• Drying time and energy consumption increased for all dryers when drying test loads that
more closely resemble real-world clothing;
• North American conventional dryers had peak power consumption roughly five times as
high as European heat pump dryers;
• Energy consumption and drying time varied significantly between the European heat
pump dryers, suggesting that labeling and incentives could be used to promote the sale
of the highest performing heat pump technologies.
Key conclusions and recommendations include:
• Heat pump dryers are a globally mature technology with substantial energy saving
potential;
• A heat pump dryer designed for North America could still offer significant energy savings
even if it were designed to sacrifice some energy efficiency in order to reduce drying
time;
• Further modifications to the new DOE test procedure, including the use of a test load
that more closely represents real-world clothing, are needed to more accurately predict arch 2013
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actual dryer energy consumption. The recently proposed 2013 revisions to the DOE
clothes dryer test procedure includes automatic termination – a significant improvement
from the current 2005 test procedure.
This study was funded by CLASP as a part of the Super Efficient Dryer Initiative (SEDI), which
brings together manufacturers, government agencies, energy efficiency program providers, and
appliance retailers in support of a North American market for new, energy efficient, advanced
dryers.
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Heat-Pump Clothes Dryers Really Work, Study Confirms
