The idea
Chilling up your ultra-low freezer from -80 to -70 has two major benefits: it can reduce energy consumption by 30%, and in doing so it can prolong the life of your freezer. This means less down time, and less chance that your samples will be compromised.
But is it safe to store my samples at -70?
In the majority of cases the answer is a resounding YES. Nucleic acids can be safely stored at -20, or -70, depending on how long they need to be stored, and most proteins can be safely stored at -70. Bacteria and viruses are also generally safe at -70. In fact, fifteen years ago all ultra-low freezers were set to -65 or -70. The drive to continually lower freezer temperatures has more to do with marketing and selling freezers than it has to do with science.
Has anyone else tried this?
YES. CU-Boulder has 60% of their ultra-low freezers set to -70. A complete list of samples that they have stored at -70 can be found here. UC Davis, Harvard, Dartmouth, UCSB and UPENN are among several universities that have participated in the freezer challenge to reduce energy consumption of ultra-low freezers by chilling them up to -70. In addition, the CDC recently raised the temperature on 60 of their freezers. Information about the CDC's efforts can be found here.
Chilling up your ultra-low freezer from -80 to -70 has two major benefits: it can reduce energy consumption by 30%, and in doing so it can prolong the life of your freezer. This means less down time, and less chance that your samples will be compromised.
But is it safe to store my samples at -70?
In the majority of cases the answer is a resounding YES. Nucleic acids can be safely stored at -20, or -70, depending on how long they need to be stored, and most proteins can be safely stored at -70. Bacteria and viruses are also generally safe at -70. In fact, fifteen years ago all ultra-low freezers were set to -65 or -70. The drive to continually lower freezer temperatures has more to do with marketing and selling freezers than it has to do with science.
Has anyone else tried this?
YES. CU-Boulder has 60% of their ultra-low freezers set to -70. A complete list of samples that they have stored at -70 can be found here. UC Davis, Harvard, Dartmouth, UCSB and UPENN are among several universities that have participated in the freezer challenge to reduce energy consumption of ultra-low freezers by chilling them up to -70. In addition, the CDC recently raised the temperature on 60 of their freezers. Information about the CDC's efforts can be found here.