Discover how UV-C technology keeps HVAC coils clean, boosts energy efficiency, and creates healthier, more comfortable indoor spaces.
Keeping HVAC systems clean and efficient is essential for both energy performance and indoor air quality. UV-C lights offer a powerful solution by targeting the microorganisms that naturally accumulate on coils and other components. By reducing biofilm, improving airflow, and limiting airborne contaminants, UV-C technology not only protects your equipment but also helps create a healthier, more comfortable environment for building occupants.
What are UV lights in HVAC systems?
UV lights used in HVAC systems are typically UV-C lights, a specific band of ultraviolet energy with germicidal properties. Unlike visible light, which we can see and which primarily provides illumination, UV-C light operates at a much shorter wavelength. That wavelength allows it to penetrate the cell structure of microorganisms (such as mold, bacteria, and viruses) disrupting their DNA and preventing them from reproducing. In practical terms, UV-C doesn’t “clean” surfaces the way chemicals do; it neutralizes biological growth at the source.
What sets UV-C apart from other types of ultraviolet light is its effectiveness. UV-A and UV-B are commonly associated with sunlight and skin exposure, but they are far less efficient at microbial control. UV-C, by contrast, is widely used in medical, laboratory, and industrial environments because of its proven ability to control biological contamination, making it well-suited for HVAC applications where moisture and organic material create ideal growth conditions.
In HVAC systems, UV-C lights are most often installed in areas that stay dark, damp, and cool, such as cooling coils, drain pans, and inside air handlers. These conditions make coils especially vulnerable to biological buildup, which can restrict airflow, reduce heat transfer efficiency, and contribute to poor indoor air quality. By continuously bathing these components in UV-C light, the system helps prevent microorganisms from taking hold in the first place.
UV-C lights in HVAC systems use ultraviolet energy to disrupt and destroy microorganisms that accumulate on coils and internal components.
Why are HVAC coils vulnerable to biofilm and microbial growth?
HVAC systems cool indoor spaces by removing heat and humidity from the air. As air passes over a cold cooling coil, moisture naturally condenses on the coil surface. While this condensation is essential to the cooling process, it also creates an ideal environment for biological growth.
That constant moisture allows biofilm to form on coils and drain pans. Biofilm is a thin, sticky layer of microorganisms that acts like a “glue,” capturing dust, dirt, and other airborne particulates as air moves through the system. Once those contaminants adhere to the coil, they provide a steady food source that allows mold and bacteria to multiply and spread.
The problem is compounded by the conditions inside an HVAC air handler. These areas are typically dark, damp, and enclosed, with limited airflow and ongoing exposure to organic material. Together, these factors create a perfect breeding ground for microbial growth on cooling coils, drain pans, and nearby internal components.
As mold and bacteria accumulate, they don’t always stay contained. Microbial growth on coils and drain pans can shed contaminants into the airstream, distributing them throughout the occupied space. Over time, this can degrade indoor air quality and may pose both infectious and non-infectious health risks to building occupants, often without any visible warning signs.
Left untreated, biofilm buildup doesn’t just affect hygiene; it can also insulate coil surfaces, reduce heat transfer efficiency, increase energy consumption, and accelerate the need for cleaning or maintenance.
How do UV lights protect HVAC coils?
UV-C lights protect HVAC coils by using high-energy ultraviolet light to actively destroy the microorganisms that accumulate on coils and other internal components, helping improve both energy efficiency and overall indoor environmental quality (IEQ). When mold, bacteria, and other microbes are exposed to UV-C energy, their DNA and RNA are damaged, preventing them from reproducing and spreading. This effectively stops biological growth before it can establish and form biofilm on critical system components.
Once installed, UV-C lights provide continuous surface disinfection of cooling coils and drain pans, areas that are constantly exposed to moisture and most susceptible to microbial buildup. UV-C technology can help air conditioning units regain much of their original, “as-built” performance, often reducing or even eliminating the need for costly coil and plenum cleanings in as little as 90 days. And unlike mechanical washing or chemical treatments, UV-C energy penetrates deep into the coil, targeting biological buildup that traditional methods can’t reach.
Another key advantage of UV-C technology is its ability to reach deep into coil surfaces. Cooling coils have tightly spaced fins and complex geometries that make them difficult or impossible to clean completely using mechanical pressure washing or chemical treatments. UV-C energy penetrates these hard-to-reach areas, neutralizing microorganisms embedded within the coil structure itself.
By keeping coil surfaces cleaner, UV-C improves heat transfer efficiency and reduces pressure drop across the coil, which can translate to average energy savings of 10 to 25 percent while also supporting better comfort and air quality over time.
How do UV lights improve energy efficiency and system performance?
When HVAC coils become coated with biofilm and trapped particulates, their ability to transfer heat is significantly reduced. This buildup acts as an insulating layer, preventing the coil from efficiently absorbing heat from the air. As a result, the system must run longer and work harder to achieve the same cooling output, driving up energy consumption and operating costs.
Dirty coils also restrict airflow. As biofilm thickens and debris accumulates between coil fins, pressure drop across the coil increases, forcing supply fans to expend more energy to move air through the system. This added strain can accelerate wear on fans, motors, and other components while reducing overall system performance and reliability.
Research cited in industry white papers shows that UV-C systems can restore and maintain coil performance over time by continuously preventing biological buildup. In existing systems, UV-C has been shown to help return coils closer to their original, “as-built” condition, often reducing or eliminating the need for frequent chemical treatments or pressure-wash cleanings. In new installations, UV-C helps preserve that original performance from day one.
UV-C technology supports improved heat transfer, better airflow, and lower pressure drop, all of which reduce system strain. The result is a more efficient HVAC system with the potential for meaningful energy savings, more stable performance, and less disruptive maintenance over the life of the equipment.
How do UV lights improve indoor air quality (IAQ)?
UV-C lights contribute to healthier indoor air by reducing microbial growth on HVAC components and limiting the number of biological contaminants that can be released into the airstream. When cooling coils, drain pans, and other interior surfaces remain wet and unprotected, mold, bacteria, and spores can flourish. These microbes (and the fragments they shed) can circulate through the ductwork and into occupied spaces, degrading indoor air quality and potentially contributing to respiratory irritation or other health concerns. By continuously disinfecting surfaces, UV-C lamps help keep these contaminants from getting a foothold in the system.
A study from the University of Colorado Boulder has shown that ultraviolet light can also directly affect airborne biological particles like allergens, reducing their presence in the air in controlled experiments. In that study, specialized UV exposure lowered levels of common airborne allergens, such as dust mite proteins, pet dander, and mold-related particles, by roughly 20–25% within 30 minutes of treatment, and in some cases by much more with longer exposure. This supports the idea that UV technology can go beyond surface sanitation to help reduce airborne biological burden in the indoor environment.
By limiting both surface-bound and airborne microbes, UV-C systems promote improved indoor environmental quality (IEQ) and can enhance occupant comfort, particularly for people sensitive to mold, bacteria, and allergenic particles.
UV Lights: New systems vs. retrofit applications
UV-C lighting can be effectively applied in both new HVAC installations and existing systems, making it a flexible solution for facilities at any stage of their equipment lifecycle. In new systems, UV-C lights are often specified during design and installed near cooling coils and drain pans to help maintain the system’s original, “as-built” condition from day one. This proactive approach prevents biological buildup before it starts, supporting long-term efficiency, cleaner operation, and more consistent indoor air quality over the life of the equipment.
For existing HVAC systems, retrofit UV-C installations offer a practical way to address ongoing biofilm and microbial issues without major equipment replacement. UV-C lamps can be added to air handlers and coil sections to continuously suppress biological growth, helping restore coil performance and reduce the frequency of disruptive cleanings. Retrofits are especially valuable in facilities where coils are difficult to access or where shutdowns for pressure washing or chemical treatments are costly, time-consuming, or impractical.
In both cases, UV-C lighting should be viewed not as a short-term fix, but as a long-term indoor air quality and maintenance strategy. Rather than reacting to fouled coils, odors, or IAQ complaints after they arise, UV-C provides continuous protection that supports system performance, reduces maintenance demands, and helps create a healthier indoor environment over time.
What facilities can benefit from UV-C Coil protection?
UV-C coil protection is especially valuable in facilities where reliability, energy efficiency, and occupant well-being are critical to daily operations. In healthcare facilities, for example, HVAC systems must run continuously and support strict infection-control and indoor air quality standards. UV-C helps suppress microbial growth on coils and drain pans, reducing the risk of contaminants being circulated while helping systems maintain consistent performance.
Higher education campuses and K–12 schools also benefit from UV-C protection, particularly in buildings with high occupancy and varied schedules. Cleaner coils support better airflow and temperature control, while improved indoor air quality can contribute to healthier learning environments and fewer comfort complaints from students and staff.
In data centers, reliability and thermal performance are paramount. Even minor losses in cooling efficiency can increase energy use or threaten uptime. By keeping coils clean and maintaining optimal heat transfer, UV-C lighting helps data center HVAC systems operate efficiently and reliably without frequent invasive maintenance.
Office buildings and laboratories face a different challenge: balancing comfort, productivity, and operational costs. UV-C coil protection helps reduce biological buildup that can cause odors, uneven temperatures, or airflow restrictions. The result is steadier system performance, lower energy strain, and indoor environments that feel cleaner and more comfortable for occupants.
Across all of these facility types, UV-C lighting serves as a proactive solution, supporting dependable HVAC operation, sustained energy efficiency, and healthier indoor spaces over the long term.
When should a facility consider UV-C lighting?
Facilities often begin exploring UV-C lighting when recurring coil fouling or frequent cleanings become a persistent issue. If coils and drain pans require repeated chemical or pressure-wash maintenance to stay operational, it’s often a sign that biological growth is returning between cleanings. UV-C provides continuous protection that addresses the root cause rather than repeatedly treating the symptoms.
UV-C lighting is also worth considering when indoor air quality complaints or health concerns arise. Odors, comfort complaints, or sensitivities among occupants can sometimes be traced back to microbial growth inside the HVAC system. By limiting growth on coils and other internal components, UV-C can help reduce the contaminants that enter the airstream and support healthier indoor environments.
Rising energy costs are another common trigger. As coils become fouled, heat transfer efficiency drops and fans work harder to overcome increased pressure loss, driving up energy use. UV-C helps keep coils cleaner over time, supporting more efficient operation and reducing unnecessary system strain.
Facilities with aging HVAC systems or upcoming retrofit projects may find UV-C to be a smart, forward-looking addition. Integrating UV-C during system upgrades or retrofits can help preserve restored performance, reduce future maintenance demands, and extend equipment life, positioning UV-C lighting as a proactive, long-term strategy rather than a reactive fix.
How can Ketchum & Walton help you integrate a UV-C system?
Effective UV-C performance depends on proper design and placement, and that’s where Ketchum & Walton plays a critical role. We will evaluate your facility’s HVAC system in detail, including overall system design, airflow patterns, coil geometry, and access constraints, to ensure UV-C technology is applied correctly and delivers measurable results.
By analyzing how air moves through the system and how coils and drain pans are configured, Ketchum & Walton helps determine the optimal UV-C placement and application for each installation, whether it’s a new system or a retrofit. This tailored approach ensures UV-C energy reaches the areas most vulnerable to biological buildup without disrupting system operation or maintenance routines.
Beyond installation, we also focus on aligning UV-C solutions with broader goals such as system performance, indoor air quality (IAQ), and long-term operational reliability. Rather than treating UV-C as a standalone add-on, we integrate it as part of a comprehensive HVAC strategy designed to protect equipment, reduce maintenance demands, and support healthier indoor environments over time.
If recurring coil fouling or IAQ concerns are impacting comfort or efficiency, UV-C may be a smart next step. Contact Ketchum & Walton to explore UV-C integration strategies that support cleaner coils, more stable airflow, and healthier indoor environments.