UCSF research provides evidence-based practical tools to reduce ultra-low temperature freezer energy costs

A cross-functional team comprised of researchers, supply chain management, and facilities leadership, at the University of California, San Francisco (UCSF), has developed and tested a practical approach to help research institutions identify energy-intensive ultra-low temperature (ULT) freezers, prioritize replacements, and forecast potential energy and cost savings. Published in Biopreservation and Biobanking, the research provides methods that institutions can adapt to freezer fleets of different sizes and available budgets¹.

The UCSF team inventoried their fleet of over 1,200 ULT freezers, then developed a multiple regression model that estimates electricity consumption using three readily available characteristics: freezer age, storage volume, and ENERGY STAR certification status. The approach enables laboratories to efficiently identify the most inefficient freezers without the time- and labor-intensive process of installing energy monitors and analyzing electricity-use data for every freezer.

UCSF applied the methodology in a pilot program that replaced 43 inefficient freezers with 41 ENERGY STAR-certified units. The program reduced annual electricity consumption by 310,493 kilowatt-hours and annual electricity costs by $55,889, with an estimated eight-year payback on the initial investment.

The researchers also developed forecasting methods that institutions can use to compare the continued operation of conventional freezers with replacement scenarios and build a business case customized to their own ULT freezer fleet. 

Modeling projects that converting UCSF’s fleet of more than1,200 ULT freezers would reduce annual electricity use by approximately 7.9 million kilowatt-hours and save more than $1.4 million annually. Even under conservative modeling assumptions, converting UCSF’s fleet of more than 1,200 ULT freezers is projected to reduce annual electricity use by approximately 7.9 million kilowatt-hours and save more than $1.4 million each year. A subsequent Letter to the Editor of BIO² by Dean Shehu provides a downloadable spreadsheet that automates key analyses, making the published methodology easier for other institutions to apply.

References:

1. Shehu D, Kim MO, Rosendo J, Krogan N, Morgan DO, Guglielmo BJ. Institutional conversion to energy-efficient ultra-low freezers decreases carbon footprint and reduces energy costs. Biopreserv Biobank 2025;23(3):195–202.
2. Shehu D. A Downloadable Spreadsheet to Automate the Analysis Required for Large-Scale Conversion to Energy-Efficient Ultra-Low Temperature Freezers. Biopreservation and Biobanking. 2026 Jul 15:19475535261468903.