ULT Set Point Effects on RNA Quality: A Comparative Analysis

Christine Alencar, University of Virginia Facilities Management

A single ultra-low lab freezer set to -80C (current standard) can consume as much energy as a single American home. Maintaining this extreme temperature is energetically demanding and financially expensive. Adjusting an ultralow temperature's (ULT's) set point to -70C can reduce a unit's energy consumption up to 40%. With nearly 500 ULTs at UVA, shifting the community's stance on cold storage standards to -70C has the potential to save an estimated 2,250 kWh/day. Put in other terms, if half of the ULTs at UVA changed their ULT setpoints to -70C from -80C, an equivalent of ~33.5 American homes' annual energy use could be removed from our greenhouse gas inventory.

Scientists and sustainability experts want to know: Is the -80C extreme always necessary? Much anecdotal and some peer-reviewed evidence suggests that -70C is an effective freezer set point for preserving even the most sensitive lab materials including nucleic acids, proteins, bacteria, viruses, and more. Additionally, there remains no clear explanation for the industry switch to -80C in the early 2000s.

We asked researchers what would help them switch. Their answer? Peer-reviewed evidence that -70C is equal to -80C for maintaining sensitive biological materials, such as RNA. UVA researchers in the Cardiovascular Research Center teamed up with lab sustainability experts to answer this question in a quantitative and qualitative RNA-sequencing study that will be an important step in promoting -70C as the standard set point for ULTs.

Learning Objectives

  • Learn about the research study performed to answer the question of whether -70C is equal to -80C in its ability to preserve highly sensitive biological samples for up to one year under standard lab conditions;
  • Understand a researcher's hesitation in changing any lab operation that has worked for them in the past;
  • Explore creative strategies for sustainability professionals to partner with researchers to develop high-level research projects to answer the call for more peer-reviewed evidence supporting sustainable lab practices; and
  • Examine how cold storage demands fit into big-picture lab sustainability challenges as well as solutions.


From the lab bench to the air handler, Christine aligns the perspectives of researchers, health and safety experts, and energy engineers to make science work for our world. She holds a Bachelor's and Master's of Science, has training in lab ventilation and project management, and is a member of I2SL's Ventilation Effectiveness Working Group.


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