November 27, 2024
DOE Report Uncovers Persistent Challenges in GUV Lighting
Some LEDs are aging like milk, not wine — one lost nearly a quarter of its UV-C punch after just 500 hours
A newly released report by the U.S. Department of Energy (DOE) shines a spotlight on ongoing issues in the germicidal ultraviolet (GUV) lighting industry. Building on its 2023 findings, the second round of CALiPER testing reveals that GUV products often suffer from overstated performance claims, potential safety hazards, and inconsistent testing standards. The research, led by Jason Tuenge, Gabe Arnold, Margaret Axelson, and Eduardo Rodriguez-Feo Bermudez from the Pacific Northwest National Laboratory, focuses on upper-room luminaires designed to disinfect air in occupied spaces.
Part One of this series, the 2023 report, revealed startling trends of inaccuracy and ambiguity in GUV product performance claims. Of the 13 products tested that year, eight were found to have significant discrepancies between manufacturer claims and actual performance. Additionally, five consumer-oriented towers marketed as UV-C emitters were found to emit no UV-C at all or primarily UV-A, rendering them ineffective for disinfection.
These findings raised urgent questions about the reliability of GUV products at a time when their role in combating airborne diseases, such as COVID-19, was gaining attention. Recognizing the importance of accurate and safe applications, the DOE’s 2024 report narrows its focus to upper-room luminaires—devices designed to safely operate in occupied spaces by targeting the upper portion of the room. Despite progress in addressing some concerns, the report underscores that the GUV industry still struggles with data transparency, energy efficiency, and safety risks, posing challenges for widespread adoption in commercial and institutional settings.
Above: The eight products presented in the "Radiometric Testing of Germicidal UV Products, Round 2: Upper-Room Luminaires" CALiPER report.
“The lack of publicly available performance data makes it difficult for potential buyers and specifiers to identify suitable products and design GUV systems for their specific applications,” the report states, highlighting a persistent barrier for end users seeking effective solutions.
Persistent Issues in GUV Lighting
The GUV playbook still seems to have too many blank pages, leaving Lighting People squinting to figure out what works and what doesn’t. The DOE’s 2024 report builds on the revelations of its predecessor, presenting a nuanced view of the industry's current state while exposing several critical challenges:
- Incomplete Product Data: Only half of the eight tested products provided essential performance data in standard formats, leaving buyers and specifiers unable to verify claims or make informed decisions.
- Exaggerated Claims: Three luminaires claimed UV-C output levels that exceeded measured values by more than an order of magnitude, perpetuating issues of overpromising performance.
- Energy Efficiency Opportunities: Some designs achieved up to five times the efficiency of others. However, the efficiency range—0.3% to 2.1%—points to inconsistent product maturity.
- Safety Concerns: Simulations predicted that two LED and two LPM luminaires would exceed safety limits for UV exposure, raising concerns about user safety.
- Testing Inconsistencies: Measurement noise affected the accuracy of testing results, reducing UV-C output estimates by up to 29% after data adjustments.
- Longevity Questions: Some LEDs are aging like milk, not wine — long-term tests revealed rapid depreciation in some LED products, including one that lost 24% of its UV-C output after just 500 hours of use.
Safety Risks and Market Transparency
The CALiPER report delves deeper into safety risks, particularly for upper-room luminaires. Two LPM products directed over 50% of their UV output into lower portions of the room, potentially exposing occupants to unsafe levels of UV radiation. Another product, with its maximum intensity aimed slightly downward, was found to violate UL 8802 safety thresholds.
Adding to the challenge is the lack of readily available performance data. Of the eight luminaires tested, only four provided standardized radiant intensity distribution files—a critical tool for designing effective GUV systems. This lack of transparency remains a major obstacle for widespread adoption, leaving potential buyers reliant on incomplete or misleading claims.
Toward a Safer, Efficient Future
Despite these challenges, the DOE report identifies opportunities for improvement. The efficiency of LPM luminaires could be enhanced by up to 75% through improved reflector designs, while LEDs, with their directional light output, are emerging as viable competitors. However, ensuring safe and effective applications will require stricter adherence to performance standards and improved product transparency.
The report concludes that while progress has been made since 2023, significant work remains to standardize testing, verify safety, and enhance efficiency. With further innovation and stricter regulations, GUV lighting has the potential to transform air disinfection in commercial and institutional spaces.
