our certifications

upright model

ENERGY STAR® Partnership

In May 2017, the ENERGY STAR® certification standards for ultra-low temperature freezers were announced by the EPA. Following that announcement, Stirling Ultracold became the first ENERGY STAR partner to be certified under the newly created laboratory grade ULT freezer category.

SU780XLE Certification

Our upright ULT freezer, the SU780XLE, received its certification based on test results obtained from a 2016 independent study that followed the ENERGY STAR test protocol. The study was prepared for California utilities by the Center for Energy Efficient Laboratories (CEEL).

Test Results

The report validated the SU780XLE’s “weighted average” (-75°C) steady-state energy consumption as .29 kWh/day/ft3. This was nearly 50% below the published Maximum Daily Energy Consumption requirement for ULT certification (.55 kWh/day/ft3). In addition to steady-state energy consumption, the ENERGY STAR test protocol includes a door-opening test, which also validated the XLE’s industry-leading energy efficiency in the 2016 report.


The Journey to Certification

From the beginning, Stirling Ultracold was a strong proponent of the ENERGY STAR Final Test Method that led to the ULT freezer certification. As an energy-efficiency industry leader from our inception, we wanted to bring ULT energy consumption to the forefront of the research community. After several years of industry collaboration with the EPA, an agreed-upon ENERGY STAR Final Test Method standard was established in 2014. This led to the third-party testing protocol that is now used in the U.S. to certify ULT freezers through authorized certifying bodies.