Indoor air quality (IAQ) has become a central focus for commercial tenants, facilities managers, building owners, leasing agents, and property owners.
One technology option for airstream and HVAC surface disinfection in this regard is ultraviolet energy in the C-band or germicidal wavelength (UV‑C). When incorporated into HVAC air handlers, UV‑C systems help inactivate airborne pathogens, mold, and bacteria, contributing to healthier indoor environments.
Since the 1990s, ultraviolet light has been used to enhance HVAC efficiency, improve air quality, and reduce energy consumption. However, the roots of germicidal UV technology go back much further. In 1937, epidemiologist William F. Wells demonstrated its effectiveness by installing UV lamps in Philadelphia schools, lowering measles infection rates to 14.5% compared to 55.3% in schools without UV‑C.
This early success in reducing airborne pathogens above people’s heads laid the foundation for today’s widespread use of UV technology in maintaining healthier indoor environments.
Building on these early successes, the focus of UV technology has continued to evolve. This article examines the benefits of UV‑C disinfection technology in HVAC air handlers. It explores how integrating UV monitoring systems with building automation systems (BAS) or building management systems (BMS) enables real-time oversight, thereby enhancing efficiency and promoting energy savings.
The Benefits of UV-C in HVAC Air Handlers
1. Improved IAQ: UV‑C technology has been widely recognized for its ability to inactivate airborne microorganisms, including bacteria, viruses, and fungi. By installing UV lamps within HVAC air handling units (AHUs) or positioning them near ceilings in occupied spaces, these harmful contaminants are effectively neutralized, significantly reducing the risk of airborne disease transmission.
The use of a single upper-room UV‑C fixture can increase the rate of decay of airborne organisms, achieving an effect equivalent to 10 air changes per hour. This is particularly beneficial in high-traffic areas such as office buildings, retail centers, hospitals, and schools, where reducing the spread of disease is essential.
2. Reduction of Biofilm and Mold Growth: The dark, moist environment inside HVAC AHUs provides ideal conditions for mold and biofilm to grow on cooling coils and drain pans. This microbial buildup can foul coils, prompting the system to work harder by lowering chiller temperatures, increasing chilled water flow, or boosting fan speed—all of which raise energy consumption and operational costs.
Organic contaminants obstruct heat transfer by forming an insulating layer on the coil surface, reducing the system’s cooling efficiency. Installing UV‑C lamps downstream of the cooling coil helps prevent microbial growth, thereby minimizing pressure drops and ensuring optimal heat exchange.
3. Energy Efficiency and Cost Savings: A cleaner HVAC system operates more efficiently. When biofilm and mold accumulate on cooling coils, they create an insulating barrier that forces fans and compressors to work harder, increasing energy consumption. Studies show that UV‑C systems can improve coil efficiency by as much as 10-20%, resulting in lower energy costs and extending equipment life. Reduced maintenance needs further contribute to cost savings, as cleaning requirements decrease and system downtime is minimized.
4. Extended Equipment Lifespan: UV‑C systems help protect HVAC components by preventing the buildup of organic matter that can lead to coil fouling, reduced heat transfer, and overall system inefficiency. By maintaining cleaner coils and drain pans, UV‑C technology prolongs the lifespan of AHUs and reduces the need for frequent component replacements, ultimately lowering long-term maintenance costs.
Linking UV Monitoring to BAS/BMS for Optimal Performance
Monitoring UV intensity and performance is crucial to maximizing the effectiveness of UV‑C systems. By integrating UV monitoring systems with BAS/BMS, facilities managers can gain real-time insights into system operation and optimize performance.
1. Real-Time Performance Monitoring: UV intensity naturally degrades over time, requiring periodic lamp replacement to ensure optimal disinfection. Integrating a UV monitoring system with a BAS/BMS allows facilities managers to track lamp intensity in real time and receive alerts when levels fall below target ranges. This proactive approach ensures that the UV‑C system consistently operates at peak performance.
2. Predictive Maintenance and Automated Alerts: BAS/BMS-integrated UV monitoring can eliminate the need for routine maintenance checks by enabling predictive maintenance. Facilities managers receive automated alerts when a UV lamp approaches the end of its lifecycle, allowing for timely replacement and minimizing the risk of system downtime. This ensures maintenance is performed only when necessary, optimizing both efficiency and cost.
3. Comprehensive Monitoring: Some UV monitors are equipped with sensors specifically configured for the traditional UV‑C (254 nm), UV‑C LED, and the emerging Far-UV (222 nm) UV‑C wavelengths, helping ensure accurate lamp performance detection across the entire spectrum.
Conclusion
Integrating UV‑C disinfection technology within HVAC air handlers can be a game-changer for enhancing IAQ, improving energy efficiency, and extending equipment lifespan. UV‑C technology delivers significant energy savings and reduces maintenance requirements by disinfecting airstreams and preventing microbial buildup on critical components. When combined with UV monitoring systems and integrated into BAS/BMS, facilities managers gain real-time oversight, enabling predictive maintenance and energy optimization—resulting in cleaner air, greater efficiency, and long-term cost savings.
The president and founder of Aerapy UV Disinfection Technology, Annette Uda is an ASHRAE member and a corresponding member of the ASHRAE Technical Committee 2.9 and ASHRAE SPC-185.5, devoted to Ultraviolet Air and Surface Treatment. She may be reached at auda@aerapy.com