One new Ultra-Low Temperature (ULT) Freezer uses enough energy to power a single family home. Freezers alone account for 2-6% of total campus energy.

A well-maintained freezer uses up to 25% less energy than a freezer that has not been maintained. Implementing freezer management best practices reduces operating costs, reduces freezer failure, ensures optimal freezer performance and lifespan, and reduces your lab's carbon footprint. 

Download and review the Lab ULT Freezer Care Poster. Follow these steps to reduce the energy consumption of your ULT.

Chill Up ULT freezers

  • Join the Chill Up movement by resetting your -80ºC freezer to -70ºC. This change can reduce ULT energy consumption by another 42%.
  • Read the Chill Up Info Sheet to learn how this increases your freezer lifespan and saves energy.
  • Identify the person in charge of freezer(s).
  • Get approval by PI/Lab Manager to chill up freezer(s).
  • Once your freezer has been Chilled Up, post the "I’m Chilled Up" sticker (available from on the ULT near the temperature display.
  • Call your freezer “Ultra Low” not “-80.”

Resources and Case Studies

Minimize Open-Door Time

Minimizing door opening will help save energy and protect samples.

  • Think about samples you need before opening the door.
  • Minimize door opening by 5 minutes per day to save 3 kWh/day.
  • Use Minimize Door Opening Tracking Sheet and apply "Minimize Door Opening" sticker.
  • For every 1 minute a ULT door is open, 10 minutes are needed to get back to the starting temperature.

Store Smart Samples Practices

Good sample management will minimize the time the freezer door is open, save space, ensure sample security and increase efficiency of lab time.

  • Consolidate and properly label samples.
  • Keep good sample records/inventory.
  • Clean out your ULT and discard any unnecessary samples.
  • Watch the brief “Be smart, Store smart” video on freezer management and sample storage.

Defrost & Maintain Practices

Properly maintained freezers help reduce energy and prolong the life of your ULT.

  • Defrost freezers annually or sooner if there is ice buildup.
  • Fill open spaces with frozen water jugs to reduce the amount of air the freezer cools.
  • Create a defrost and maintenance schedule and assign a responsible person.

Retire & Replace Practices

An old ULT can consume twice as much energy compared as a new one.

  • Upgrade old ULTs to more energy efficient ones. Energy Star certified models are now on the market! Green Labs offers an energy efficient ULT rebate. Learn more and apply here.
  • Turn off, remove and dispose of freezers that are not in use.
  • See if your lab qualifies for an energy efficient ULT rebate.