By Jasmine Simpson, Campus as Living Lab Student Fellow
The Freezer Inventory Project, launched in late 2023, aims to improve the efficiency of a major energy hog: ultra-low temperature freezers.
Stepping inside a research laboratory, you will inevitably see a few key types of equipment: microscopes, fume hoods, lab coats, and, maybe most important, freezers. Ultra-low temperature (ULT) freezers regularly operate at temperatures around -80°C, preserving sensitive biological materials for research. The catch? ULTs are massive energy hogs. A single freezer consumes about 30 kilowatt-hours per day, roughly the same as an average American household. Multiply that by the 1,620 freezers located in labs across Penn’s campus, and it becomes no surprise how labs account for 37% of Penn’s carbon emissions – a bigger emitter than even offices, classrooms, and residence halls.
Labs have thus become a critical focus in Penn’s Climate and Sustainability Action Plan 4.0, leading to the development of a Green Labs Program. Supported by a collaboration between the Office of Environmental Health and Radiation Safety (EHRS) and the Penn Sustainability Office (PSO), Green Labs aims to enhance both safety and sustainability by educating and empowering lab staff to engage with greener practices.
When Alisha Ramirez became the first full-time staff member of Penn’s Green Labs Program in 2023, ULT freezers were one of her top priorities. “Freezers are one of the most energy-intensive pieces of equipment,” Ramirez explains, “so making sure that [they] are running efficiently helps everyone.” Not only does freezer efficiency move Penn closer to its climate goals by lowering energy use, but it also ensures better protection of sensitive lab samples crucial for research. The challenge until recently, however, was that there was no comprehensive way to track these freezers and their condition. This changed with the launch of the Freezer Inventory Project.
The project, though simple in concept, is labor-intensive. It involves locating freezers across campus, assessing their condition, and recording observations in an online inventory system managed by EHRS. Behind the scenes, Ramirez has verified and uploaded the data for 825 freezers assessed thus far, setting the foundation for future sustainability projects.
Green Labs interns have been essential to these inventory efforts, leveraging the campus as a living lab to advance their education and campus sustainability at the same time. 2025 graduate Srishti Jainapur, for example, wrote her capstone for the Master of Environmental Studies program on freezer optimization. Her research projected that Penn could save $1.3 million and 9,519 megawatt-hours of energy annually by adopting sustainable cold storage management practices, such as raising freezer setpoints by 10°C, cleaning filters, and removing frost buildup. To spread awareness and support labs in adopting these practices, PSO partnered with external technicians to provide free on-site repairs during the 2025 Energy Week at Penn. This successful event will be repeated during the upcoming Energy Week to be held on campus in February 2026.
Other initiatives include PSO’s ULT Freezer Rebate Program, which helps labs replace old units with newer, energy-efficient models. Labs can also recycle abandoned freezers – often left running unnecessarily – and receive $500 to cover costs and incentivize action. Just last year, 19 freezers were replaced and three recycled.
Beyond technical fixes, the mission of the Freezer Inventory Project relies on the collaboration of lab personnel to engage with sustainable practices. When analyzing participation, Jainapur noted that only about 30% of lab staff responded to outreach. Ramirez understands why: “They obviously have their research and work, [so] sustainability initiatives can sometimes feel like another thing added to their work scope.” Her approach thus focuses on making changes accessible and rewarding through incentives, shout-outs, and gratitude. “I try to build [sustainable practices] into [day-to-day work] and make it more of a natural feeling,” she reflects. This idea of longevity stems from adopting not just sustainable practices, but a sustainable culture.
While efforts like Green Lab Certification – an external certification program currently being piloted at Penn that recognizes the depth and breadth of lab sustainability practices – can provide external incentive, sometimes internal motivations matter most. That’s where students come in. “They bring a fresh set of eyes,” Ramirez says, “and if they’re building those sustainability practices in the lab from the get-go, then that can start to make a positive change in the overall lab environment.”
This ripple effect – seeing and learning from one person to motivate change – is real and transformative. The School of Dental Medicine, as an example, has become a campus leader in lab sustainability thanks to the efforts of Laura Sprague, an administrative and quality assurance manager. Among other endeavors, Sprague worked with Ramirez and Marta Guron, project manager in EHRS, to donate glass pipettes that were sitting unused to teaching labs in the Chemistry Department, diverting 117 pounds of waste and saving more than $3,000. Ever since, Ramirez has sought to find more of these champions and provide them with support to create cultural change and shared responsibility within their own labs.
To continue building on this momentum, a short-term goal of Ramirez’s is to see Penn leading in sustainable practices through increased participation in the International Freezer Challenge, an international competition that focuses on sustainable actions taken in cold storage management. Although last year marked Penn’s most successful year in the challenge, ranking 18th place out of 112 academic organizations across 29 countries, still only 25 of Penn’s 750+ labs participated across campus.
Thinking more long-term, Ramirez hopes to work with student interns and staff to perform preventative maintenance, create best-practice manuals, and recycle abandoned freezers, inventorying all campus freezers and turning the ripple of sustainable lab work into a wave.
For more information on making labs greener, visit the Green Labs Program.