How to pick the most energy efficient freezer

Credit: Flickr user proteinbiochemist / CC BY-NC 2.0 "in the -80"

The use of -80F freezers is a significant source of greenhouse gas emissions on campus. According to data compiled on the Labs 21 Energy Efficient Equipment wiki, the direct cost of electricity use for an individual freezer could be between $1000 and $1500 per year (at $0.15/kWh, not including the indirect cost associated with providing additional cooling to dissipate the heat generated by these units). In 2008, Stanford commissioned a study which found that its 2000 freezers were costing the university $5.6 million per year to operate.

Not all -80F freezers are created equal. Even among the brands identified by Labs 21 as energy efficient, there is a factor of 2 difference between the most energy efficient option per cubic foot of storage space and the least efficient option. The following table shows you which ones come out ahead, and you can get the most up to date raw data from Labs 21.

Here’s how you can use this information to make a difference:

• Evaluate potential freezer purchases on their longevity and their absolute energy use (or their space-normalized energy use (per ft³) if your sample collection is rapidly growing).
• Share freezers with neighboring labs if possible.
• Adopt energy efficient freezer maintenance procedures (defrosting, vacuuming dust from coils, check door seals, etc…).
• Encourage your lab group to clear out any clearly unneeded samples from past researchers, to delay the need to purchase any new freezers.
• Consider using existing technologies that allow you to store dehydrated DNA and RNA at room temperature for extended periods of time without degradation.

Want information on other types of energy efficient equipment? Check out our guide to sustainable lab purchasing!