How in the World Did CU Boulder Green Labs Convince Scientists to Make the Switch From -80C to -70C?!

Ashlyn Norberg, University of Colorado Boulder

The University of Colorado (CU Boulder) has been working with labs to increase the temperature of Ultra Low Temperature (ULT) freezers from -80C to -70C for energy savings and to extend the lifetime of freezers. Based on metered data, raising the temperature typically saves 2-4 kWh/day, but has been greater in some cases. This presentation will address how the CU Boulder Green Labs Program worked with labs to increase the temperature on ULT freezers, the correlation between temperature and energy, common items stored at -70C, and will provide resources for other campuses to encourage lab users to increase ULT freezer temperatures.

Learning Objectives

  • Learn how CU Green Labs worked with labs to increase ULT freezer temperatures
  • Learn how CU Green Labs addressed concerns raised by scientists
  • Understand what energy savings can result from raising the temperatures of ULT freezer from -80⁰C to -70⁰C
  • Raised awareness of what resources are available to assist in ULT temperature changes at other campuses


Ms. Norberg has been working with Kathy Ramirez-Aguilar and the CU Green Labs program for four and a half years while working towards her B. S. in Environmental Engineering. Her work has focused on reducing energy consumption, solid waste production, and water use in the research labs on campus. As one of the first staff members, she has been instrumental in helping to build the program, engaging lab members, and keeping the operation of the program going.


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