Pull-down time to -80 °C
After installation as well as after de-frosting of the ULT freezer, the freezer needs to pull-down to -80 °C as soon as possible. In general, a good ULT freezer just needs 4 to 5 hours to pull-down from room temperature to -80 °C, saving precious time and protecting your samples. The short pull-down time is of high value for potential backup freezers: They are required to be ready in the shortest time possible. Therefore, many labs keep one backup freezer running 24/7, resulting in high power consumptions.
Based on fast pull-down times, backup freezers do not need to run all the time. They are ready within a short timeframe of within 4 hours. On top, the samples within the broken freezer unit are safe as the insulation slows down the sample warm-up.