Ultra low temperature freezers, also known as minus 80 freezers, are an essential piece of equipment in laboratories and certain medical facilities. They provide a way to preserve biological samples and vaccines by keeping them at very low temperatures. Their operating temperature may range from -45°C to -89°C. Several features make an ultra low freezer an extremely reliable solution for laboratory research and other critical applications.

Green Cooling specialise in the design and installation of energy-efficient ultra low freezers for medical and laboratory facilities. We have put together this guide to help you learn more about how these units work. If you’d like to enquire about our bespoke ultra low temperature freezer solutions, get in touch with our team today.

Types of Ultra Low Freezers

There are two basic types of ULT (ultra low temperature) freezers: upright freezers and chest freezers. The latter is more efficient than the former, but is generally not preferred because of usual space and convenience limitations.

ULT freezers have a selection of internal storage layouts or compartments, often reconfigurable by the user. For example, they may have combinations of adjustable and exchangeable doors, shelves, baskets, trays or special racking systems designed for the storage of a wide range of refrigerator and freezer accessories, including cryogenic boxes, vial storage systems or cryotubes.

You may need a bespoke solution to suit a certain application. If this is the case, reach out to our team who will be able to help you find a solution. 

Features of Ultra Low Freezers

  • Energy-efficient, microprocessor-controlled freezing systems
  • Digital, user-friendly touchscreen displays
  • Lockable, card-entry or self-closing doors for sample security
  • Over-temperature alarms
  • Remote temperature monitoring with USB downloads
  • Inner doors and high-efficiency foam insulation to minimise temperature losses
  • Highly efficient pump systems for fast cool-down times
  • Safety back-up systems in the event of a power or mechanical failure

How much temperature variation inside can be expected?

A ULT freezer with the most optimum temperature uniformity should be selected. While temperature fluctuation is just a few degrees away from the set point, reviewing the manufacturer’s test data is the best solution.

The exact location of the testing probes, usually top, bottom, and middle of the inner chambers should be specified by the data. The data should also explain the amount of load in the freezer during the time of testing. A fully loaded freezer ensures a better uniformity.

Energy concerns

A ULT freezer will cause additional heat load and this fact should be known to the facility manager. As part of the energy management strategies, this additional heat load can be mitigated by consolidating all the freezers into a single room with sufficient cooling, or dispersing the additional heat load by separating the ULT freezers to various locations.

New developments in the compressor design of ULT freezers, cabinet design and insulation have led to better efficiencies for storing samples. Yet, despite this fact, the efficiency of ULT freezers may reduce over time with time because of refrigerant loss, loosening seals, poor maintenance, fatigue in mechanical systems, or degraded lubricants. 


Regular maintenance of ultra low freezers is essential to ensure optimal performance and maximum energy efficiency. In the case of the Pfizer Covid-19 vaccine, maintaining the required low temperature is a matter of life and death, so equipment should be regularly inspected for any faults. 

Condenser filters should be regularly checked, washed, cleaned, or replaced, and coils should be cleaned with a wet towel, brush, or vacuum. Condenser filters can be reused and hence do not have to be replaced.

Green Cooling

Green Cooling can provide purpose-built ultra low temperature freezers suitable for medical and laboratory use. They can maintain temperatures of -70°C and lower, for the safe and effective storage of vaccines or biological samples. 

With a track record of providing highly efficient cooling solutions in the Hospital & Public Sector, Green Cooling are on hand to help. If you’d like to learn more about our bespoke ultra low temperature freezer solutions, for the storage of vaccines or other scientific uses, get in touch with our team today.

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