For more than 80 years, Sub-Zero has set the standard for luxury kitchen appliances. The family-owned company, headquartered in Madison, Wisconsin, is known for engineering products that not only store and preserve food but also elevate the entire kitchen experience. 

Each refrigerator is designed to last more than 20 years, featuring NASA-inspired air purification and precise temperature control that keeps food fresher for longer. Produce like lettuce stays crisp for up to two weeks longer than in a typical refrigerator. Building appliances that last isn’t just about mechanical excellence, but a relentless focus on quality at every step of the product lifecycle.

Historically, Sub-Zero’s appliances were primarily electromechanical, and quality assurance was focused on precise manufacturing and assembly. But as appliances evolved into intelligent, software-defined systems, Sub-Zero recognized their testing also needed to evolve. To uphold their 20-year longevity promise, they needed a validation approach that could ensure reliability while scaling increased product complexity.

A pivotal moment came when the Sub-Zero team attended the Hardware in the Loop is for Everyone session at NI Connect, which demonstrated how HIL—traditionally associated with aerospace and automotive—could also be an ideal fit for white goods.

Since they were already using NI LabVIEW and NI CompactDAQ, adopting the NI LabVIEW+ Suite was a natural next step. This unified platform streamlines the development and deployment of complex test systems, including hardware-in-the-loop (HIL) testing for real-time appliance simulation.

Together, these technologies empower Sub-Zero to:

• Simulate appliance behavior using NI LabVIEW models 
• Run thousands of test cases without needing physical prototypes 
• Automate regression testing, reducing validation time from weeks to hours 
• Ensure safety and reliability by testing fault conditions in a controlled environment 

“When the brand promises a 20-year life, it’s a serious responsibility for test engineering. So, we test everything,” says Chase Fearing, LabVIEW Architect at Sub-Zero. 

Sub-Zero’s testing journey illustrates how a scalable, integrated platform enables sustained innovation without sacrificing quality. By building three HIL systems using NI LabVIEW+ Suite, including NI VeriStand (for real-time simulation) and NI TestStand (for test automation), Sub-Zero can now model, simulate, and automate real-time testing with greater precision and efficiency. 

The NI LabVIEW+ Suite for HIL, which bundles essential software tools under one license, provides Sub-Zero with the flexibility and integration needed to scale testing efforts and streamline workflows as their products become more complex.

This comprehensive approach enables engineers to identify issues early, iterate faster, and ensure that even the most sophisticated software components uphold Sub-Zero’s legendary standards.

“We’ve already seen a lot of success, and HIL is becoming a strategic differentiator for testing appliance software,” Chase adds.

Sub-Zero’s investment in NI-powered test systems has delivered tangible benefits.

• Improved safety: Fault conditions can be tested without risking damage to physical appliances. 
• Faster development: Automated testing accelerates validation cycles, enabling shorter time to market. 
• Higher quality: Software bugs are caught earlier, reducing the risk of costly recalls or customer dissatisfaction. 
• Team empowerment: Engineers at all levels, including interns, can contribute to the testing process thanks to the intuitive environment. 

For Sub-Zero, our strategic partnership supports their quality-first ethos with expert guidance and customer education. This relationship is critical as Sub-Zero evolves from a traditional manufacturing company into a technology-driven innovator. By embracing HIL and automated testing, they’re not only preserving their legacy of quality—they’re future-proofing it. 

“Working together has been a gamechanger. With dedicated account managers, expert training, and the right mix of technical expertise, guidance, and support, this partnership gives us everything we need to succeed and drive real results.”

Although Sub-Zero’s primary market is the U.S., international sales are growing—and bringing new regulatory requirements and testing needs. NI’s flexible platform positions them well to adapt. 

Sub-Zero demonstrates how intelligent test systems empower companies to maintain exceptional product reliability, even as complexity continues to increase. By deeply embedding test into their product lifecycle and leveraging the evolving NI technology suite, Sub-Zero is well-positioned to continue delivering appliances that redefine kitchen quality and longevity for decades to come.