RACA Journal May 2025 RACA_May2025 | Page 5

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OPEN-SOURCE VS PROPRIETARY SOLUTIONS IN HVAC SYSTEMS

By Eamonn Ryan derived from the presentation by Robert Fox

In a recent SAIRAC Johannesburg Centre TechTalk, Robert Fox, national president of SAIRAC and senior cost and design estimator at Club Refrigeration, discusses the ongoing debate between open-source and proprietary solutions in HVAC systems.

With over 31 years of experience, Fox shares his deep knowledge of the challenges and benefits of each approach, offering a nuanced perspective on their application in the industry.

Fox begins by exploring proprietary HVAC systems, which are designed, controlled and maintained by specific manufacturers. These systems often come with closed-source software and hardware, meaning that users need to purchase a license to access or modify the source code. The licensing model attached to these systems involves strict legal agreements that restrict alterations or redistribution unless explicitly allowed by the manufacturer.

The key advantage of proprietary systems lies in their reliability and their ability to meet strict industry regulations. Many proprietary solutions are designed to comply with important standards, such as FDA 21 CFR Part 11, which ensures the electronic records and signatures are maintained according to regulatory specifications. In industries like pharmaceuticals and food storage, where temperature and environmental control are critical, these systems are often indispensable. Fox stresses that proprietary systems are favoured because of their reliability, ease of use, and assurance of compliance with industry standards. For instance, many proprietary systems are already compliant with industry-specific standards like FDA regulations, making them the go-to choice in highly regulated environments.

OPEN-SOURCE SOLUTIONS’ FLEXIBILITY AND CUSTOMISATION On the other hand, open-source HVAC solutions provide more flexibility. With open-source software, the source code is freely accessible and can be modified to meet the unique needs of a project. This flexibility allows HVAC professionals to tailor systems to their specific requirements without being bound by licensing agreements. However, a key distinction of open-source solutions is that contributors must be acknowledged when

redistributing the software, unlike proprietary systems, which may place additional restrictions on redistribution.

Despite these advantages, Fox points out the limitations of open-source solutions. For example, open-source systems typically lack the formal certifications and testing required for highly regulated environments, such as those governed by the FDA. This absence of regulatory compliance makes open-source solutions unsuitable for certain applications where certification is critical. Furthermore, liability is a

Robert Fox, national president of SAIRAC.

significant concern. If an open-source HVAC system were to fail in a high-risk environment, such as a cold storage facility, the financial and reputational risks could be considerable, making businesses hesitant to adopt open-source systems.

COEXISTENCE OF OPEN-SOURCE AND PROPRIETARY SYSTEMS Fox emphasises that open-source and proprietary systems can coexist within the same environment, depending on the application. The choice between the two comes down to several factors, including the complexity of the system, regulatory requirements and liability concerns. In some cases, open-source systems may provide the flexibility needed for specific tasks, while proprietary systems may be required in more complex or regulated settings.

A significant portion of Fox’ s talk focused on the programming side of HVAC systems. As HVAC systems grow more sophisticated, integrating custom software becomes increasingly important. Fox discussed Python as an ideal tool for programming HVAC systems, highlighting a library called BAC0, which simplifies the development and customisation of HVAC control systems. Python’ s simplicity and versatility allow HVAC engineers to create tailored solutions with greater flexibility.

Fox explains that while Python is accessible to those new to programming, developing HVAC controllers requires a solid understanding of communication protocols like LonTalk /

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