Stirling ULT25NEU Portable Ultralow Freezer

by Stirling

SKU 2543F FREEZER

FULLY TESTED & WARRANTIED*

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Shipping

All products ship from our 30,000 sq. ft. Haverhill, MA warehouse

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Call 978-521-2221
to request information & pricing for item 2543F FREEZER

Stirling ULT25NEU Portable Ultralow Freezer

The Stirling Ultracold ULT25NEU Portable Ultra-Low Freezer is a compact, energy-efficient ultra-low temperature storage solution engineered for reliable sample protection in laboratories, clinical facilities, pharmaceutical environments, field research applications, and biobanking operations. Designed to maintain stable temperatures as low as -86°C without conventional compressor-based refrigeration, the ULT25NEU delivers dependable ultra-low storage performance with dramatically reduced energy consumption and quiet operation.

Stirling ULT25NEU Portable Ultralow Freezer features

Temperature range: -20°C to -86°C for ultra-low sample preservation
Compact 25-liter capacity ideal for portable and benchtop applications
Free-piston Stirling engine technology eliminates conventional compressors
Energy-efficient design consumes significantly less power than traditional ULT freezers
Quiet operation with low vibration for laboratory and clinical environments
Rapid pull-down and temperature recovery performance for sample protection
Lightweight portable design supports transport and mobile laboratory applications
Environmentally friendly refrigerant-free cooling system with reduced heat output
Digital touchscreen controller with programmable alarms and temperature monitoring
90 day warranty from American Instrument Exchange

Professionally refurbished by American Instrument Exchange each Stirling Ultracold ULT25NEU Portable Ultra-Low Freezer undergoes comprehensive testing and validation to verify ultra-low temperature performance, alarm functionality, and overall operating condition—providing laboratories with dependable ultra-low storage at substantial savings compared to purchasing new equipment.

With a vehicle adapter the Stirling ultralow ULT25NEU can be used in applications that require portability, such as pharmaceutical distribution. Other uses include pathology laboratories, tissue banks, regenerative medicine, and other applications related to clinical or diagnostic medicine.

Featuring compact dimensions and highly energy-efficient Stirling engine cooling technology, the ULT25NEU is widely used for laboratory overflow storage, vaccine transport, biologic preservation, clinical research, pharmaceutical storage, and field sample transport applications where reliable ultra-low temperatures are required in a small footprint.

Unlike traditional compressor-based ultra-low freezers, the Stirling ULT25NEU operates using a single moving piston system that reduces vibration, minimizes maintenance requirements, and significantly lowers power consumption while maintaining stable ultra-low temperatures. The freezer’s low energy draw and reduced HVAC load make it particularly attractive for laboratories focused on sustainability and operational efficiency.

Applications include vaccine and biologic storage, clinical and hospital laboratory use, pharmaceutical sample storage, field and mobile laboratory research, biobanking, and transportation of temperature-sensitive materials.

CLICK HERE to see the Stirling ULT25NEU portable ultralow freezer on our YouTube channel

Stirling ULT25NEU Portable Ultralow Freezer - Specifications

Model: ULT25NEU
Capacity: 25 Liters
Temperature Range: -20°C to -86°C
Voltage: 100-240V, 50/60Hz
Cooling Technology: Free-piston Stirling engine
Refrigeration System: Compressor-free ultra-low cooling
Controller: Digital touchscreen interface
Mobility: Portable benchtop design
Noise Level: Low-noise operation
Energy Features: Energy-efficient low power consumption design

For inquiries about the Stirling ULT25NEU, please give us a call at 978-521-2221, or fill out the form on this page.

Testing

Most of our equipment is used and reconditioned. Our technicians verify the accuracy of temperature controls and readouts of all freezers, making sure that the units hold temperature to within the manufacturer specified tolerance. We replace any hardware or parts as is necessary and if needed replace refrigerant. We clean all freezers thoroughly prior to shipment.

Pictures

The photos of the Stirling ULT25NEU Portable Ultralow Freezer above are representative. Please bear in mind that the equipment shown is currently in storage in our warehouse and that in addition to testing each machine we will clean all the equipment thoroughly prior to shipment.

We often have multiple units of each model in stock and sometimes we're unable to feature photos of every single unit. At your request, we can provide photos of the equipment in your order after testing and cleaning.

Stirling ULT25NEU Portable Ultra-Low Freezer – Frequently Asked Questions (FAQ)

What is the Stirling ULT25NEU used for?

The Stirling ULT25NEU Portable Ultra-Low Freezer is designed for portable ultra-low temperature storage of sensitive materials such as:

Biological samples (DNA, RNA, vaccines)
Clinical trial materials
Cell and gene therapy products
Pharmaceutical and diagnostic samples

It is lightweight and can plug into a variety of power soruces. This makes it especially suited for cold-chain transport and remote storage applications.

What makes this freezer unique?

The ULT25NEU stands out because it is a fully portable ultra-low freezer (−80 °C class) that is also compatible with AC and DC power, including vehicle use. Additionally, the cooling is based on Stirling engine technology, not compressors, meaning it is lightweight and dependable. This model is suitable for field deployment and clinical environments.

Does the Stirling ULT25NEU support remote monitoring?

Yes. Many customers choose to use the ULT25NEU with cloud-based monitoring systems, continuous logging of temperature and system status, alerts for deviations to provide both peace of mind and traceability.

What are the installation requirements?

Minimal setup is needed for this unit, meaning deployment is quick and easy. All you need it a standard electrical outlet or DC source, adequate ventilation, and a stable surface or transport mount. Beyond that, no special facility infrastructure is required.

How energy efficient is the ULT25NEU?

The Stirling ULT25NEU is significantly more energy efficient than many traditional cascade refrigeration ultra-low freezers. Its Stirling engine cooling system reduces electrical consumption and lowers HVAC heat load within the laboratory environment.

How stable is the temperature inside the unit?

The freezer is engineered to maintain stable ultra-low temperatures with rapid recovery after lid openings. The Stirling engine cooling system provides highly responsive temperature control for protection of sensitive biological and pharmaceutical materials.

Testing Procedures for Used and Refurbished Ultralow Freezers
Ensure -80°C Stability and Critical Sample Protection

Used and refurbished ultralow freezers from American Instrument Exchange are rigorously tested to ensure reliable long-term storage at temperatures as low as -80°C. Each unit undergoes a detailed inspection, full system evaluation, and extended runtime testing to meet the high standards required by research, clinical, and biorepository environments.

Why Testing Used Ultralow Freezers Is Essential

Before an ultralow freezer is placed back into service, it must be carefully tested for:
• Temperature stability and uniformity at ultralow levels (e.g., -70°C to -86°C)
• Cascade refrigeration system functionality and compressor health
• Seal and insulation effectiveness to prevent thermal loss
• Electrical safety, alarm functionality, and system compliance

Thorough testing helps prevent temperature excursions and equipment failure—crucial for protecting sensitive materials such as biological samples, vaccines, enzymes, and research specimens.
Our structured ULT testing protocol ensures each refurbished unit delivers dependable performance and long-term reliability.

Key Testing Procedures for Refurbished and Used Ultralow Freezers

1. Initial Visual Inspection

• Inspect external cabinet, hinges, and door gaskets for wear, corrosion, or damage
• Check power cords, plugs, and control interfaces for signs of wear or tampering
• Verify that internal racks, shelving, and chamber components are intact and operational

2. Functional Startup and Control Testing

• Power on the unit and confirm successful initialization of digital displays and alarm systems
• Test control panels, keypad responsiveness, and user-setpoint functionality
• Verify that door seals close tightly and form a secure barrier

3. Temperature and -80°C Stability Testing

• Test and evaluate internal temperature sensors thermometers/probes
• Monitor temperature performance at multiple chamber points over extended runtimes
• Confirm uniformity and stability at key setpoints, including -70°C, -80°C, and -86°C

4. Refrigeration System and Cascade Compressor Evaluation

• Test dual-stage (cascade) compressor function, startup times, and cycling behavior
• Evaluate evaporator coils, heat exchangers, and vacuum insulation panels for performance and integrity
• Check for refrigerant leaks, low-pressure faults, and abnormal compressor noise

5. Alarm and Safety System Verification

• Test high/low temperature alarms, power failure alerts, and battery backup systems (if equipped)
• Verify lockout controls, alarm delay settings, and door-open indicators

6. Final Quality Assurance and Documentation

• Run a continuous multi-day test cycle at -80°C to confirm sustained performance
• Document temperature logs, controller accuracy, and compressor behavior
• Complete a detailed service report

Dependable Performance from American Instrument Exchange

All refurbished ultralow freezers from American Instrument Exchange are tested to exacting standards for performance, safety, and reliability. With our rigorous inspection and testing procedures, you can trust your ULT freezer to deliver consistent -80°C storage from day one—ideal for research, clinical, pharmaceutical, and biobanking applications.

Repair and Refurbishment Protocol for Used Ultralow Freezers
-80°C Storage Performance from American Instrument Exchange

At American Instrument Exchange, every used ultralow temperature freezer (ULT freezer) undergoes a rigorous, multi-step refurbishment protocol designed to restore reliable -80°C performance. Whether upright, chest-style, or undercounter, our refurbished ULT freezers are tested and restored to deliver the cold storage precision required for biological samples, vaccines, enzymes, and other temperature-sensitive materials.

Why Choose a Refurbished Ultralow Freezer from American Instrument Exchange?

• Fully tested for -80°C cold storage stability and compressor performance
• Backed by a warranty
• A cost-effective alternative to expensive new ULT units
• Environmentally responsible through equipment reuse and waste reduction
• Serviced by experienced technicians specializing in laboratory-grade refrigeration

Step-by-Step Ultralow Freezer Refurbishment Protocol

Every ultralow freezer sold by American Instrument Exchange is carefully evaluated and restored through the following process:

1. Initial Intake & Inspection

• Exterior inspection for dents, corrosion, or physical damage
• Evaluation of door seals, hinges, and internal chamber components
• Documentation of missing parts or components requiring repair

2. Cleaning and Decontamination

• Comprehensive interior and exterior cleaning using non-abrasive cleaners
• Removal of dust, frost buildup, and residual contaminants
• Decontamination of all internal surfaces and removable parts like shelves and drawers

3. Mechanical and Electrical Repairs

• Replacement or repair of worn or damaged components (door latches, hinges, gaskets, etc.)
• Inspection and repair of control boards, displays, sensors, and switches
• Electrical system evaluation, including fuses, wiring, relays, and connectors

4. Ultralow Refrigeration System Assessment

• Testing of dual-stage compressors and cascade cooling system
• Evaluation of heat exchangers, evaporator coils, and vacuum insulation panels
• Inspection for refrigerant leaks, low pressure, or signs of compressor fatigue
• Verification of thermal insulation integrity

5. Temperature and Performance Testing

• Testing of internal temperature sensors and controllers
• Multi-point testing to verify chamber temperature uniformity at -80°C
• Long-duration, multi-day operational testing to ensure sustained ultralow performance

6. Safety and Compliance Checks

• Electrical safety testing and grounding verification
• Alarm function tests for high/low temperature alerts and power failure warnings

7. Final Quality Control and Documentation

• Multi-day runtime validation at -80°C
• Recording of temperature logs, compressor cycle data, and performance benchmarks
• Final inspection and service/testing report completed

Trust the Experts at American Instrument Exchange

With over 50 years in the lab equipment industry, American Instrument Exchange is your trusted source for refurbished ultralow freezers. Our certified refurbishment protocol ensures each ULT freezer delivers the precision, performance, and reliability your lab needs—at a fraction of the cost of new equipment.

Warranty Information

All used equipment sold by American Instrument Exchange is refurbished/reconditioned, tested to meet specifications, cleaned, and comes with a 90-day warranty from the date of shipment unless otherwise specified. New products include a warranty from the manufacturer. Your warranty is only valid if you have paid your invoice. If your invoice is over 30 days old, warranty work will not be performed until your invoice is paid in full. American Instrument Exchange is not liable for any special or consequential damages that result from the use of, or the inability to use, the materials on this site or the performance of the products,

Exceptions include international sales and items that are agreed to be sold with a lesser warranty or items that are agreed to be sold “as is.”

Should there be visible shipping damage to packaging or concealed shipping damage to item(s) supplied, buyer must communicate such damage to the delivering entity or carrier upon receipt first and to American Instrument the same day item is accepted / signed for. Failure to do so voids warranty. Customer decision to involve / procure third party or OEM service other than American Instrument or AIE assigned vendors to resolve in-warranty instrument failure or defect without first placing a service call to American Instrument voids warranty.

Return & Cancellation Policy

American Instrument Exchange will authorize the return of and issue a full refund for any equipment that is not working as represented and could not be replaced or repaired to the customer’s satisfaction by AIE or a representative of AIE during the warranty period. Returns without prior authorization and an RMA number will not be accepted.

Customers are responsible for proper packaging of the equipment and all included accessories. American Instrument will pay for insurance and shipping costs. Non-inventory items bought specifically to fill customer orders may possibly be returned, but on a case by case basis.

Customers who cancel orders after refurbishing has begun or after delivery where there are no equipment performance issues may be subject to a Restocking/Cancellation Fee of 20% or more and responsible for shipping costs for both the delivery and return.

Ongoing and Extended Support Options

American Instrument Exchange is able to provide additional repair and support services outside the warranty terms for most products that sell.

For biosafety cabinets, clean benches, chemical fume hoods, and other clean air products our team at AIE Laboratory Services can provide certifications, repairs, decontaminations, and other services for customers throughout New England, and guidance and limited technical assistance for any customers in the US and Canada for new or refurbished biosafety cabinets purchased from American Instrument Exchange.

For all other products, the repair service team at American Instrument Exchange can provide both field and depot repair evaluations. We can easily schedule and coordinate the pick-up and transportation of your malfunctioning equipment. By offering hourly rates lower than most OEM service providers and eliminating travel time for technicians, we help reduce repair costs. Furthermore, our lab depot repair service minimizes or eliminates scheduling delays. Our experienced service technicians are qualified to restore your equipment to factory specifications.

Please contact our team at info@americaninstrument.com for more details.

FAQ

Does the equipment come with a warranty?

Yes, all equipment from American Instrument Exchange comes with a warranty.
Used/reconditioned/refurbished equipment is tested to make sure it operates to the manufacturer’s specifications and comes with a 90-day warranty (unless otherwise noted). New equipment comes with a warranty from the manufacturer.

How do you test and recondition the equipment?

Testing requirements vary across all the equipment categories we sell. Temperature controlled units are tested with NIST traceable probes and data loggers. Gaskets, external housing, glass, handles, controls and control screens are all thoroughly inspected for integrity and functionality.
We test all equipment using the manufacturer's parameters and specifications to confirm that the unit operates properly. While we may not be able to test for specific analytical applications we do our best to simulate the conditions under which the equipment will be used in your lab. If you have particular testing requirements please let us know and we’ll work with you to make sure these are addressed during testing.

How do products ship from American Instrument Exchange?

We can ship products both nationally and internationally using a well-established network of transporters. Smaller items will ship via UPS. Larger equipment will be palletized and shipped either LTL or air-ride, depending on the specific equipment and/or delivery requirements. In many cases we can offer inside delivery. Customers are also welcome to make pick-up arrangements using their own preferred carrier.

All shipments are FOB Haverhill, MA. American Instrument Exchange will take reasonable steps to protect the equipment during shipment and the equipment will be fully insured. The customer will be charged for all shipping and handling charges, and fees incurred in the process of delivering the order.

For local customers in and around New England we can offer shipping and delivery using a local moving company trained by our staff to handle and deliver lab equipment. Our local movers can provide either standard dock-to-dock delivery or bring the equipment into your lab and set it in place.

Prior to signing the POD (Proof of Delivery), you are responsible for inspecting the goods for any damage. You MUST note any damage on the POD prior to letting the driver leave. This is to protect you, the receiver of the goods in the unlikely event of any damage. Once you sign the POD free and clear from damage, the goods are then deemed delivered in good order and no further claims would be applicable. This is the standard for all transportation so we want to protect you, our valued client.

Return and order cancellation policy

American Instrument Exchange will accept the return of any product that is not working as represented and could not be replaced or repaired to the customer’s satisfaction by American Instrument or a technician hired by/vetted by American Instrument Exchange’s during the warranty period. The customer will be responsible for proper packaging of the equipment and all included accessories.

Customers who cancel orders after refurbishing has begun or after delivery where there are no equipment performance issues will be subject to a cancellation and restocking fee of between 20% and 40% and responsible for the full total of the shipping & handling costs for both the delivery and the return of the equipment.

Are discounts available for educational or non-profit institutions, or for bulk purchases?

Yes – call or email us today with a list of equipment you’re looking for and we can potentially put together a quote that includes a discount.

How does your price matching policy work?

We strive to keep our pricing competitive and reasonable. If you find comparable items for sale at a lower price from other vendors please send us a link and or quote for the item and we’ll do our best to match or beat the price.

Can I see the equipment in person before committing to a purchase?

Customers are welcome to make an appointment to view equipment in our warehouse. Given our workload we may not be able to test or clean the equipment prior to your arrival if you have not committed to an order.

1023 Western Avenue is a working warehouse, not a showroom, and customers should dress appropriately and wear closed toe shoes.

Can I ship products that I purchased elsewhere to American Instrument for repair?

Yes – please see our repair services page for more information.