If you work in Biology, BioE, Chemistry, or even Chem or MechE or DMSE, chances are that your lab has an Ultra Low Temperature Freezer (ULT) - often referred to as “Minus 80”s due to the fact that in recent decades they have been standardized to a set point of -80° Centrigrade.

These behemoths keep your samples cool and protected, but that comes at a cost. The average compressor-based ULT uses 12,000 kwh per year - that’s as much as a standard family home in the United States! What can we do about this problem?

Read about how the Prather Lab in ChemE was featured in ACS for chilling up their ULT Freezers!


As mentioned above, just because you think of a ULT as being “Minus80” certainly does NOT mean that your samples need to be kept that cold!

Extensive research has been done internationally to prove that the extra 10°C provides no benefit to your samples, yet uses up to 30% more energy than setting your freezer to -70°C.

The University of Colorado Boulder has over 50% of its ULTs on campus at this setpoint, with schools like UC Davis, Harvard, and more joining the club. “Chilling up” is the new trend in earth-friendly research!

CLICK HERE for a list of samples across the country that have been stored successfully at -70°C or warmer

Biogen Chillup Graph 2019.png

Biogen recently completed a study examining the energy saved by increasing their freezers 10°C…check out the savings here!
An average of 34%, or 1500 kWh/year!

PEER REVIEWED PAPERS proving the efficacy of long-term -70°C or warmer storage:

Stability of HCV, HIV-1 and HBV nucleic acids in plasma samples under long-term storage MartaJosé, RodrigoGajardo, Juan I.Jorquera Volume 33, Issue 1, March 2005, Pages 9-16


Older models of ULTs, like many electric appliances, use considerably more energy to stay at temperature than their new, EnergyStar or compressor-less counterparts.

MIT has partnered with MassSave and Eversource to offer cash incentives to labs who purchase newer appliances that reduce their plugload. You can get up for $1,500 off the purchase of an efficient freezer - plus ensure your lab saves energy for the decades that it will be in use!


It’s very possible your lab keeps an extra ULT around for back up, or has multiple ULTs running with only 50% capacity. Not only does a poorly organized freezer mean wasted space, but your compressor will actually thank you for filling in those empty spaces! The more “dead space” that a ULT has to keep cold, the harder it has to work, and the sooner it will fail - consider consolidation, or offer the space to neighboring labs in need!

Join the freezer challenge!

This national competition “promotes sample accessibility, sample integrity, reduced costs, and energy efficiency by harnessing a spirit of competition within and between laboratories. Challenge participants use well-evidenced criteria and best practices that support science quality and resilience while minimizing total costs and environmental impacts of sample storage.” Best part? You get a chance to win a ticket to the I2SL conference!