An ultra-low temperature (ULT) freezer is often the most valuable single instrument in a lab — not because of its price, but because of what's stored inside it. Choosing the right one, and protecting its contents, is worth getting right.
What ULT freezers are for
Ultra-low freezers operate between -40°C and -86°C, far colder than a biomedical freezer. That range is needed for long-term storage of plasma, cell lines, DNA and RNA, reagents and other biologicals that degrade at warmer temperatures. If your samples must survive months or years, this is the equipment that protects them.
Upright vs chest
- Upright ULT freezers save floor space and make organised, indexed access easy — the usual choice for busy labs cycling samples in and out.
- Chest ULT freezers hold their temperature longer during a power failure because cold air sinks and stays in the box when the lid is closed — useful where outages are frequent and access is less often.
Match the format to how you'll actually use it, then confirm the internal capacity in racks or boxes, not just litres.
Confirm it truly reaches -80°C under load
A freezer rated to -86°C should reach and hold your working set-point (commonly -80°C) with a full load, not just empty. Ask about pull-down time and temperature stability, and — for a refurbished unit — that the compressors and controls have been tested to that specification.
Backup, alarms and monitoring
Because the contents are irreplaceable, protection matters as much as the freezer itself:
- Remote and local alarms for high temperature and power failure.
- Backup systems — CO₂ or LN₂ backup injection where samples justify it.
- Continuous monitoring so a drift is caught early, day or night.
Ventilation, heat and power
A ULT compressor rejects significant heat and draws real power. Plan for adequate room ventilation or cooling, sensible clearance around the cabinet, and an electrical supply (and ideally generator/UPS backup) that can carry it. A ULT freezer in a hot, unventilated room works harder and lasts less.
Why refurbished ULT can be excellent value
New ULT freezers are expensive. A certified refurbished unit from a proven manufacturer — with its refrigeration system serviced and validated — can protect your samples just as well for far less, freeing budget for backup and monitoring. Browse our ultra-low freezers, including certified refurbished Sanyo and Panasonic models in upright, chest and VIP-series designs.
The short checklist
- Upright or chest, matched to access and power reliability
- Confirmed performance to your set-point under load
- High-temperature and power-failure alarms plus monitoring
- Backup injection where samples justify it
- Adequate ventilation, clearance and backed-up power
- For refurbished: serviced, validated refrigeration and a warranty