A Guide to: Medical Freezers

A guide to medical freezers graphic by CoolMed

Although not as commonly used within healthcare facilities as medical fridges, medical freezers still play an important role in maintaining public health.

Most scientists and healthcare practitioners working in research hospitals, laboratories and pharmaceutical companies rely on medical freezers to protect and extend the shelf life of the biological specimens they work with.

What is a medical freezer?

Medical freezers, also known as medical-grade, pharmaceutical or laboratory freezers, are designed to keep healthcare products that require freezing stored at the correct temperatures.

Certain vaccines, medications and clinical samples require freezing to keep them from spoiling. Medical freezers are expertly designed to preserve the integrity of these products by ensuring temperature stability and uniformity.

Medical freezers, which are used to store healthcare products such as plasma and the chickenpox vaccine (or any vaccines that contain varicella), store these products at a temperature between -16oC and -24oC.

Certain products, such as Pfizer’s recent Covid vaccine, DNA and red blood cells can be stored for months, if not years, if kept in a reliable, ultra-low temperature (ULT) freezer.

What is an ultra-low temperature freezer?

An ultra-low temperature freezer stores contents at a temperature between -40oC and -86oC. ULT freezers are also commonly referred to as “minus 80 freezers” or “negative 80 freezers” – both terms refer to the most common ULT standard.

In contrast to short term biological sample storage (usually between +8oC and -20oC), which can be achieved with a standard medical fridge or freezer, many molecular biology and life science laboratories require long-term cryopreservation, which can only be achieved with a ULT freezer.

ULT freezers keep biological samples such as DNA, RNA, proteins, cell extracts and reagents safe from sample damage.

Important features of medical freezers

At CoolMed,our standard medical freezers come in 2 different sizes – small and medium, however they’re both packed with features that enable the safe storage of vaccines and biological samples that require freezing.

Lockable doors

All CoolMed medical freezers are lockable. We provide 2 keys with each freezer unit, ensuring products within the freezer remain as safe as possible. If you’re worried about key loss, we can provide our freezers with a keyless combination lock for a small extra fee.

iCool temperature probe

All our medical freezers come with a built-in iCool temperature probe, which accurately monitors and stabilises drug and sample temperatures, ensuring they don’t become spoiled.

Temperature display with battery backup

CoolMed freezers all feature an external digital temperature controller and display with battery backup. Temperatures can be read, recorded and reset with just the touch of a button. In the event of an electricity outage, the battery backup will continue to monitor the internal temperature of the freezer, preventing products from spoiling.

Flexible storage

All our medical freezers come with multiple shelves/drawers that can be inserted into a variety of shelf locations. All our freezer shelves have a back stop, which prevents products falling down the back of the freezer and becoming unusable.


CoolMed freezers all feature a factory fitted porthole. This enables quick and easy access for any secondary temperature monitoring probes.

Spark free units

At CoolMed, none of our freezers are fitted with internal lights or fans. They’re not needed, and it also allows our freezer units to be used in laboratories that require electrical goods to be spark-free.

Features of ULT freezers

Ultra-low temperature freezers are designed first and foremost to protect and extend the life of biological samples and specimens.

ULT freezers are mainly used in used in biobanking and pharmaceutical laboratories to store proteins, DNA, antibodies, enzymes and other samples critical for biological research. They typically store thousands of pounds in products, sometimes for years on end.

ULT freezers feature all the qualities of standard medical fridges, but are more robustly built, which allows them to store products at such low temperatures. Other features include:

Solid steel cabinet design

Our ULT freezers are constructed of rugged stainless steel, so they’re able to withstand incredibly low temperatures. The outer doors and panels achieve exceptional insulation ratings via vacuum panels. Airtight closures maintain ultra-low temperatures and are assured with triple point seals around door closings.

Audio and visual alarms

Our ULT freezers are fitted with audio and visual alarms that will alert you if the temperature within your freezer fluctuates outside its designated range. This allows issues to be resolved in a timely manner and prevents samples from spoiling due to increased temperatures.

How do medical freezers differ from domestic freezers?

Unlike domestic freezers, medical-grade freezers are designed to experience little temperature fluctuation and have acute temperature control systems to maintain extremely low temperature readings.

For example, CoolMed medical freezers all feature an external temperature display that can be powered by a battery back-up in the event of a power cut. This ensures the internal freezer temperature can still be monitored, even without mains electricity.

Most domestic freezers are readily available and relatively cheaply made, whereas medical freezers are often solid steel structures. This extends their lifespan and means they can be relied on to store important medical supplies.

Medical freezers are also equipped with locks to prevent unauthorised access and to ensure products within them are kept as safe as possible.

How to choose the right medical freezer for you

When buying a medical freezer, it’s important to find a freezer that’ll meet the needs and size of your facility. To make sure you choose the right freezer for your organisation, keep the following factors in mind:

Freezer size

Balancing the amount of storage space you need with the floor space you have available is an important factor to consider. Our small, countertop medical freezer is a compact size and is perfect for sitting on a table top or in any laboratory where space is an issue. Its storage capacity is a surprisingly spacious 47 litres even though it only measures 598x595x519mm (WxDxH).

If you need something slightly larger, think about investing in an undercounter or bench side freezer. The CoolMed medium medical freezer has a storage capacity of 115 litres and will sit perfectly under any countertop. If you plan on growing your sample inventory, then selecting a larger model with room to grow will benefit you in the long run. 

* It’s important to note that medical fridges should never be more than 75% full to allow airflow throughout the freezer and to prevent a build-up of frost. This may mean investing in a larger freezer than you initially intended to buy.


Unlike domestic freezers, medical freezers provide accurate, uniform and sustainable temperatures to ensure biological and medicinal products are stored safely.

It’s important to consider what products you need to store before selecting the freezer you’re going to buy. Standard medical freezers store products at temperatures between -16oC and -24oC, however if you need to store DNA, tissue samples and other similar products for long periods of time, you’ll need to invest in a ULT medical freezer. ULT freezers are designed to maintain temperatures down to as low as -86 °C.


Budget constraints can greatly affect the size and type of freezer you opt for. Start by figuring out what products you need to store, and how long for. This will determine whether you need to invest in a standard medical freezer or a ULT freezer.

An ultra-low temperature freezer represents a substantial investment but may be necessary if you require a long-term storage solution for thermosensitive samples such as genetic material.

Once you know the type of medical freezer you require, take storage capacity into consideration and have a budget in mind when shopping – this will prevent you from overspending.

Get in Touch 

If you’d like to speak to us about our range of medical freezers, or would like to discuss what medical freezer would suit your organisation best, please call 0161 772 5666, or email us at info@coolmed.co.uk. Our team will be happy to help!