In terms of performance, users should keep in mind that “the warm-up time during a power failure, pull down time, uniformity and recovery time after a door opening are all critical to the daily conditions that samples are subjected to. If the unit is incapable of buffering the daily swings in temperature, the samples will be subject to degradation,” says Ted Andrew, Product Manager for New Brunswick Scientific.

Units must also offer storage flexibility, such as adjustable shelving, to allow better utilization of available space and more accurate control of stored samples.

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Also of importance is the need for reliable warning systems – both visual and audible – to signal temperature deviation or, in the case of power failure, warn of interruption or irregular fluctuation in temperature. Some manufacturers now offer a remote alarm contact for external monitoring of the alarm systems for additional security.
 
In terms of energy efficiency, “The end users should take a long look at the kw/h consumption rates especially in multi-unit facilities. With energy costs skyrocketing, the yearly operating differences between manufacturers can be $1000/year,” says Andrew.
 
Regarding footprint, “In most laboratories, the difference between a few cm here and there on equipment can be the difference between meeting and failing safety code aisle space restrictions,” adds Andrew.  
 
Compressor design is also important. In the case of one manufacturer, a low stage compressor cycles off when the set point temperature is reached, extending compressor life, decreasing noise levels and reducing power consumption.