Analysis of Air-Conditioner Selection in Laboratories: Common Misconceptions About Multi-Split and Split Systems and How to Make a Rational Choice

The air-conditioning system is a critical piece of laboratory infrastructure, directly impacting the operational stability of precision instruments, the reproducibility of experimental data, and the overall quality of the research environment. In selecting HVAC solutions for laboratories, the relative merits of VRF systems versus conventional split‑type air conditioners have long been a subject of debate. Many industry‑wide assumptions contain significant inaccuracies, often leading to equipment mismatches, elevated energy consumption, and potential operational risks. Drawing on real‑world operating conditions in laboratories, this paper identifies and corrects common misconceptions, objectively compares the actual performance of these two system types, and provides professional, impartial guidance for laboratory projects worldwide.

The architectural logic of the two systems differs fundamentally: multi‑split units belong to a centralized HVAC system, with a single outdoor unit interconnected to multiple indoor terminals. Leveraging inverter‑driven technology and intelligent control, they precisely allocate refrigerant based on the real‑time cooling load of each zone, enabling independent temperature regulation by zone and on‑demand output. By contrast, split‑type systems employ a one‑to‑one independent architecture, where each outdoor unit corresponds to a single indoor unit; air conditioners in different rooms operate independently, without interconnection, resulting in a fully decentralized temperature‑control configuration. This structural distinction directly accounts for the performance gap between the two in professional laboratory settings.

The industry generally assumes that multi‑split systems have high failure rates and complex maintenance, but this misconception conflates structural complexity with the likelihood of breakdowns. While multi‑split units do incorporate more precision‑engineered components, top‑tier brands can achieve mean time between failures exceeding 20,000 hours, making their overall reliability comparable to that of high‑end split systems. Moreover, multi‑split systems feature a modular design; standardized installation practices provide dedicated service access and piping shafts, allowing isolated faults at individual terminals to be repaired without disrupting the continuous operation of the entire system. By contrast, in multi‑room configurations, split systems tend to have numerous, widely dispersed fault points, and their outdoor units are often mounted on building façades, requiring elevated work for maintenance or replacement—resulting in higher operational risks and long‑term costs.

“The notion that multi‑split systems consume more energy” is the most widely held misconception, yet it bears no resemblance to actual laboratory test results. Laboratory conditions—characterized by continuous heat dissipation, year‑round uninterrupted cooling, and uneven load distribution across zones—perfectly align with the technological strengths of multi‑split systems. Under partial‑load operation, multi‑split units can achieve 30%–50% higher efficiency, support cross‑zone heat recovery, and enable highly efficient energy reuse, delivering overall performance that significantly outpaces that of split‑type systems. Measured data show that, in standard laboratory operating scenarios, multi‑split systems can achieve annual energy savings of 20%–35%, whereas split systems lack system‑level energy‑management capabilities, resulting in persistently high overall electricity consumption when operated in a decentralized manner.

At the condensate‑control level, condensation is a universal physical phenomenon in all air-conditioning systems; the real differentiator lies in the system’s ability to manage it holistically. Multi‑split units are equipped with high‑precision temperature‑and‑humidity control algorithms that dynamically optimize evaporator temperature, minimizing condensation at its source. They also come standard with a dedicated condensate lift pump and a sealed drainage pipeline, ensuring orderly water discharge and completely eliminating the risks of water pooling and leakage. By contrast, split‑type units feature a decentralized, haphazard drainage layout that is prone to pipe blockages and poor drainage; over time, this can foster mold growth, compromising the laboratory’s cleanroom environment.

In terms of operations and maintenance, split‑type systems may appear easy to operate, but they incur higher lifecycle O&M costs. Frequent high‑altitude work on the outdoor units, coupled with a wide variety of equipment models, places significant strain on spare‑parts inventory and makes centralized monitoring difficult, resulting in lower fault‑diagnosis and response efficiency. By contrast, multi‑split systems enable intelligent, centralized management across the entire facility; they allow real‑time remote monitoring of equipment operating conditions and automatic fault‑code identification. With outdoor units centrally located on equipment floors or rooftops—eliminating the need for high‑altitude work—and supporting non‑stop, modular maintenance, these systems substantially boost O&M efficiency while reducing management costs.

Faced with the stringent environmental requirements of laboratory settings, the performance gap between the two systems becomes even more pronounced. Multi‑split systems can maintain temperature fluctuations within ±0.5°C, meeting the rigorous standards of various precision experiments and instrument calibrations, whereas split systems typically exhibit temperature variations exceeding ±2°C. Moreover, multi‑split units seamlessly integrate with fresh‑air ventilation, filtration, and differential‑pressure control systems, aligning with laboratory cleanroom and ventilation specifications—capabilities that split systems lack. In addition, multi‑split systems deliver stable cooling even in low‑temperature environments as low as −15°C, supporting year‑round continuous operation in laboratories, while conventional split units experience a significant drop in performance under such conditions, often leading to shutdown or failure.

There is no universally superior or inferior air-conditioning solution—only one that best suits the specific application. For small, simple laboratories, temporary projects with constrained renovation conditions or limited budgets, split‑system units offer cost‑effectiveness and ease of installation, making them a viable choice. However, for modern, specialized laboratories that demand long‑term operational stability, precise environmental control, intelligent operations and maintenance, and energy efficiency and cost reduction, multi‑split systems—with their comprehensive performance advantages—represent the most practical and forward‑looking solution available today. By dispelling entrenched industry biases and selecting equipment based on objective operating conditions, we can ensure a stable, reliable environment that supports scientific research.