Four Factors to Consider When Buying an Ultra-Low Temperature Freezer

Research before you buy

Published: Tuesday, July 12, 2022 - 11:02

Ultra-low temperature freezers became popular due to the storage of Covid-19 vaccines, but they have been important components of laboratories for many years. There’s a lot, however, to think about—quality, productivity, maintenance, different types of technology, warranties, etc. And if you end up with the wrong unit, you could incur unnecessary expenses or delays.

In this guide, we’ll talk about some of the most important factors when purchasing an ultra-low temperature (ULT) freezer so you can end up with the right unit for your laboratory needs and budget.

Types of ultra-low temperature freezers

An ultra-low temperature freezer is a unit that preserves and stores biological samples within a temperature range of -50°C to -86°C. First, let’s quickly review the two different types of ultra-low temperature freezers:

Upright freezers: Uprights have a similar configuration to refrigerators, take up less space in a lab, and offer better organization. The upright configuration also makes samples more accessible.
Chest freezers: These do a better job than upright freezers of holding temperatures during door openings. They are typically not as popular because they can take up a large amount of floor space.

Four factors to consider when buying a ULT freezer

Before you make your next purchase, here are six important considerations:

1. Reliability

Obviously you want a reliable piece of equipment—but how do you know which manufacturers and models are the best?

Do your research. Read reputable blog posts and lab equipment guides. Talk to current and former colleagues and see which products they recommend (or which ones they don’t, which can be equally valuable information). Read online reviews, and research equipment manufacturers. Look for companies with proven records of reliability. And if you need ultra-low temperature vaccine storage, make sure the model you’re looking at is compliant with CDC and Vaccine for Children (VFC) storage guidelines.

Make sure you have the proper amount of voltage coming to your freezer. Any place can have voltage fluctuations—especially during the summer. A dip in voltage can really affect the compressors and cut the unit’s life short. You want to make sure the voltage coming to that freezer is stable.

2. Technology

For the most part, ULT freezers have two compressors that work together to achieve the required ultra-low temps. This is commonly called a cascade refrigeration system.

If one compressor fails, the other compressor cannot maintain the temperature and the whole system will fail—thus destroying your samples.

There is a newer technology involving a cascade refrigeration system that enables one compressor to maintain temperature if the other fails. For normal operation, it is more efficient to have the ultra-low freezer use both compressors working together to achieve and maintain the -80°C temperature.

The benefit of this new TwinGuard technology is that if something should go wrong with one of the compressors, the system will switch to use just one of the compressors to maintain -80°C.

This is unique because standard units won’t be able to hold -80°C if one of the compressors fails. The main benefit is that this kind of technology offers extra protection in the event of a service issue.

The only drawback is that these units are a little more expensive. But many customers find the extra cost worth the peace of mind to keep their samples safe.

It’s important to note, however, that if you have this kind of technology, you still need to call the service company so the unit can be repaired. But at least your samples will not be destroyed.

Another big change—some new units do not use as much energy. Older freezers have been known to use as much energy as a single-family home in the United States, resulting in a big push in the industry for equipment to be more energy efficient.

Many companies have come out with new compressor technology and hydrocarbon refrigerants to meet these new standards. To help quantify which units use “less energy,” Energy Star started to certify ULT freezers. You can visit Energy Star’s website to see which units carry that certification. 

3. Maintenance and warranty

As with any type of lab equipment, you should schedule regular preventative maintenance. With ultra-low temperature freezers, this includes checking and cleaning the condenser filter every two to three months—a simple but effective task that only takes a few minutes.

Another maintenance challenge you may encounter is ice buildup on the doors. Some models offer removable inner doors, which come off easily with no tools required. This makes it much easier to defrost the doors—you just remove the door, close the outer door, and allow the ice to melt. If the inner door is not removable, you must leave the outer door open for several minutes and chip away while using an ice scraper—similar to removing ice from a car in the winter. Not only is this more time-consuming, but it can create quite a mess. Plus, your outer door is open for a longer period of time, meaning the freezer could warm up.

Ice racks are another consideration. These help reduce ice buildup and add another layer of organization.

Besides regular maintenance, is there anything you can do to prevent major repairs? Should you consider a preventative maintenance plan? These are all important questions to ask.

All types of lab equipment come with a warranty. But there are restrictions. A typical warranty covers parts but not labor, which is the most expensive part of most repairs. Some warranties require a preventative maintenance program, and if you don’t have this your warranty isn’t valid.

4. Productivity and security

For added peace of mind, consider a unit that includes a CO₂ backup system. In the event of a mechanical problem or a power outage, this option would allow the freezer to maintain -70°C. Additionally, a monitoring system will alert you if the freezer is becoming too warm.

You could also add inventory racks to increase efficiency. Without these racks, you are searching in the freezer trying to find your samples; It’s more time-consuming and keeps the freezer door open longer. 

The bottom line: Will the ultra-low temperature freezer work for your research and lab? Will it accomplish your goals and help you move forward in your work? You want a unit that provides the features you need, such as temperature monitoring and alarms. You need to consider how the freezer handles frost and ice buildup, the external dimensions of the unit, whether it will fit comfortably in your lab, voltage requirements, etc.

Ultra-low temperature freezer FAQs

Q: How much space does an ultra-low temperature freezer need around the unit?
A: Most manufacturers say 4-in. to 6-in.

Q: Is the shelving fixed or adjustable?
A: The shelving is easily adjustable, and you can always add more shelves depending on your needs.

Q: What is the voltage, and what kind of plug comes with the freezer?
A: You may see a few different voltage options, but 110, 115 and 120 VAC are basically the same. Most manufacturers list their voltage requirements as 115 VAC in this lower range. In North America, the terms 220, 230, and 240 VAC all refer to the same voltage level. Most manufacturers list their requirement as 220 VAC in this higher range.

The plug configuration will change depending on your selection, so it’s best to consult with your sales rep for all the details.

At the end of the day, purchasing any type of lab equipment is an important decision. Ultra-low temperature freezers are no exception.

About The Author

Jamie Steiner

Jamie Steiner is the regional sales manager of DAI Scientific and leads a team of 13 equipment sales consultants. His background includes 20 years of experience working with customers in academic, clinical, industrial, and bio/pharma laboratories. He works with architects, engineers, and lab planners to identify the correct equipment for each user’s specific needs, and leverages his previous role as a DAI sales representative to help his sales consultants work with customers to ensure informed decisions and customer satisfaction. He holds a bachelor’s degree in communications from the University of Wisconsin-Whitewater.