-70 ˚C/-80 ˚C Comparison Pilot Program
Trying to convince your lab that samples don't have to be stored at -80 ˚C?
We are, too! We have an ongoing pilot comparing samples stored at -20 ˚C, -70 ˚C, and -80 ˚C to show our lab members that -80 ˚C may not be the only option for long-term storage that is safe and reliable for samples.
Read more about this initiative below, or check out our other Pilot Programs.
-70 ˚C/-80 ˚C Comparison Pilot Program
Green Labs is calling for samples for a student-led study comparing samples held at -20 ˚C, -70 ˚C and -80 ˚C in the Chen Freezer Farm.
If you are interested in contributing a sample, please email us at [email protected] or fill our this Google Form!Update: Since September 2023, we have stored and tested samples of glycerol bacterial cultures, animal cell lines, and protein.Preliminary results show that in -70 ˚C compared to -80 ˚C : bacterial biomass yield and DNA yield are consistent; and animal cell death fraction (apoptosis) is constant; and protein function and integrity is unchanged. By the start of 2025, we hope to have a finalized writeup to share, so stay tuned!
Our plan: Conduct a controlled study to provide evidence that -70 ˚C is a safe temperature for long-term storage. Samples from various labs will be tested and compared at intervals over a period of up to 5 years. We are testing the assumption that "colder is better" in terms of ultra-low temperature storage of samples. Furthermore, adjusting temperatures from -80 ˚C to -70 ˚C ensures an energy savings of up to 30%! This "chill-up" will also reduce the number of defrosts your freezer requires each year, and reduces the wear and tear on your freezer! Here are some additional resources suggesting that -70 ˚C is a safe storage temperature for many kinds of samples.
If you are interested in contributing a sample, please email us at [email protected] or fill our this Google Form!
Is keeping our ultra-low temperature freezer at -70 ˚C just as good as -80 ˚C? Short answer: YES! Here are some references to support our claim, and keep an eye out for results from our year-long study!
Sample Storage Temperature Comparisons
Caltech Sustainability -70C/-80C Case Study
Additional links with advice on how to keep your freezer running optimally:
Freezer Best Practices Overview
Improving Freezer Efficiency Is (Ultra) Cool!
9 Ways to Make Your Refrigerator More Efficient
Additional studies and links:
Caltech Freezer Rebate Program (save between $2,000 and $8,500 on a new freezer!)
MIT: Putting the Freeze on Lab Energy Waste
Useful References:
Check out the Lab Spring Clean Event for more information, freezer and inventory signage, freezer defrost guide, and more!
Cold Storage Fact Sheet (simple)
Cold Storage Fact Sheet (detailed)
Freezer Rebate Program
Caltech's High-Efficiency Freezer Program provides substantial energy and cost savings by reducing electricity consumption. New high-efficiency ultra-low-temperature (ULT) freezers use about two-thirds less energy than inefficient ones: 7–9 kWh/day versus 20–24 kWh/day respectively. The program incentivizes both the purchase and replacement of freezers.
- An inefficient ULT freezer at Caltech uses one-third more electricity than an average California household (about 24 kWh / day versus about 18 kWh / day, respectively).
- 1.3 inefficient ULT freezers at Caltech produce the same carbon emissions as an average U.S. passenger vehicle.
Interested in an ultra-low-temperature freezer rebate? Please apply using this Google doc.