FAQ

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What is Ultraviolet?

Ultraviolet (UV) light is one form of electromagnetic energy produced naturally by the sun. UV is a spectrum of light just below the visible light and it is split into four distinct spectral areas –Vacuum UV (100 to 200 nm), UVC (200 to 280 nm), UVB (280 to 315 nm) and UVA (315 to 400 nm).

The entire UV spectrum can kill or inactivate many microorganism species, preventing them from replicating. UVC energy at 253.7 nanometres provides the most germicidal effect. The application of UVC energy to inactivate microorganisms is also known as Germicidal Irradiation or UVGI. Ultraviolet CUVC exposure inactivates microbial organisms such as bacteria and viruses by altering the structure and the molecular bonds of their DNA (Deoxyribonucleic acid). DNA is a “blue print” these organisms use to develop, function and reproduce. By destroying the organism’s ability to reproduce, it becomes harmless since it cannot colonize. After UVC exposure, the organism dies off leaving no offspring, and the population of the microorganism diminishes rapidly. Ultraviolet germicidal lamps provide a much more powerful and concentrated effect of ultraviolet energy than can be found naturally. Germicidal UV provides a highly effective method of destroying microorganisms.

Some people call it dirt. Some call it mud, slime or sludge. This gluey matrix growing on heating, ventilating and air conditioning (HVAC) evaporator coils, drain pans and ducts is, in fact, biofilm. Biofilm is an active, complex microbial matrix of mold and bacteria that adheres to the fins of the coil and protects the organisms from biocides.

The biofilms themselves give off prod­ucts of metabolism known as volatile organic compounds (VOCs) which may range in effects from watery eyes and head­aches, to more severe allergy and asthma responses.

Numerous studies have demonstrated that the HVAC system is a viable amplifier, reservoir and disseminator of pathogenic and opportunistic bacteria, viruses and mold. The list below identifies some of the many microorganisms that have been isolated from evaporator coils, drain pans, ducts, final filters and diffusers.

No matter how good the coil cleaner, sprayer or pressure washer used, the effectiveness of these methods reaches about 1 inch into the coil and the organic and biologically active matter gets packed deeper into the coil fins.

Installed on air effluent side of the condensate cooling coils and the drain pan, Steril-Aire UVC energy destroys surface biofilm and airborne microorganisms before they circulate throughout the HVAC system.

Numerous studies have demonstrated that the HVAC system is a viable reservoir of pathogenic and opportunistic bacteria and mold. Below is a partial list of microorganisms that have been found on evaporator coils, drain pans and ducts:

The quality of indoor air, influenced by the levels of bioaerosols, contaminants and pollutants, can affect occupant health and development, resulting in reduced productivity and increased absenteeism. The biofilms themselves give off products of metabolism known as volatile organic compounds (VOCs) which can trigger occupant complaints of watery eyes and headaches and even severe allergy and asthma responses. The biological contaminants typically found on HVAC coils and drain pans have also been linked to Sick Building Syndrome (SBS) and hospital acquired infections.

Biological fouling of evaporator fin and tube heat exchangers is a key contributor to decreased HVAC capacity. The biological fouling acts as an insulator, increasing air flow resistance and decreasing heat transfer. The fans run longer to maintain the building at the desired temperature, increasing kW draw with reduced cooling tonnage capacity. A mere 10% increase in fan motor run can significantly increase energy use. The chillers and pumps work harder to raise the leaving water temperature and achieve set temperature points. For each degree the water temperature is increased, a savings of 1-2% will be realized.

Steril-Aire high output UVC provides continuous cleaning of coils, eliminating the biofilm that causes reductions in operational efficiency. Studies have shown that removal of a .024” layer of biofilm can reduce HVAC energy usage by 21% by restoring heat transfer and system efficiency. Reduced cooling coil pressure drop helps save fan energy, while improved cooling coil heat transfer efficiency. Higher chilled water temperature setpoints allows the chiller plant to operate more efficiently.

Manual coil cleaning can be a major HVAC maintenance expense and may be very difficult to perform on small, tough-to-access packaged or unitary systems. Manually cleaning only temporarily removes the contaminants and in most cases, simply pushes the biological contaminants further back into the fins.

Steril-Aire UVC solves these problems by eliminating the need for chemical cleaning or pressure washing of any size coil. It also eliminates the associated downtime and inconvenience. Maintenance crews and building occupants are no longer exposed to harmful cleaning chemicals and disinfectants.

The surface cleaning effects of UVC helps restore older HVAC system to efficient operation and maintain new systems at factory design efficiency, while protecting system components against the acids that are emitted from the biofilm and the corrosive effects of chemical coil cleaning.

The C wavelength of the UV spectrum targets the DNA of microorganisms, destroying their cells and making replication impossible. Directed at a cooling coil or drain pan, UVC energy destroys surface biofilm, a gluey matrix of microorganisms (bacteria, fungi, debris, et al.) that grows in the presence of moisture. Biofilm is prevalent in HVAC systems and leads to a host of indoor air quality (IAQ) and HVAC operational problems that are sometimes mistakenly attributed solely to mold. UVC also destroys airborne viruses and bacteria that circulate through an HVAC system.

By applying the power of UVC at the source of contamination – the HVAC evaporator coils and drain pan – Steril-Aire UVC destroys the reservoir of microorganisms. Without the ability to reproduce, microorganisms become inactive and harmless. The recirculating air in HVAC systems creates redundancy in exposing microorganisms to UVC, ensuring multiple passes so the light energy is effective against large quantities of airborne microorganisms. Steril-Aire UVC delivers the highest UVC output, driving HVAC system efficiency while improving indoor air quality.

Emitters are to be installed down stream of the coil horizontally across the full face of the coil without the use of reflectors in sufficient quantity and in such an arrangement so as to provide an output as specified and equal distribution of UVC energy on the coil and in the drain pan.  To maintain energy efficiency and IAQ, the UVC energy produced shall be of the lowest possible reflected and shadowed losses.

Output is critical because it affects a UVC lamp’s performance. To effectively clean coils and eliminate biofilm the UVC dose at the extreme edges of the coil shall not be less than 930 mW/cm2  and end of life intensity on the coil face shall exceed 740 mW/cm2 at the end of the 18000 hours of operation period measured in 2.0 m/s airflow at 13 Deg C.     (Necessary to remove and prevent Biofilm from forming)

Steril-Aire has developed a UVC Application Standard that includes technical data and specifications, as well as installation, sizing, dosage and other guidelines to assist in the proper selection and application techniques of UVC lamp systems.

No, Steril-Aire devices do not produce ozone or other secondary contaminants. According to the U.S. EPA, “Recovery from the harmful effects can occur following short-term exposure to low levels of ozone, but health effects may become more damaging and recovery less certain at higher levels or from longer exposures (US EPA, 1996a, 1996b).”

Dispose of them as you would any fluorescent tubes, in compliance with your country, local or state codes.

Fixture and Emitter shall be 100% warranted to be free from factory defects for a period of 18000 hours of Operation.

The Power Supplies/electronic Ballasts shall have a lifetime warranty

The use of Steril-Aire UVC may contribute to LEED points across multiple project types in one or more of the following areas: Energy and Atmosphere, Water Efficiency, Indoor Environmental Quality, Innovation & Design Process and Regional Priorities.
Read how one city government building earned LEED credit

Steril-Aire UVC emitters use high-output germicidal light to eliminate airborne and surface pathogens inside the air handling unit. By destroying mould spores, bacteria, viruses, and VOCs at the coil and in the airstream, Steril-Aire improves indoor air quality (IAQ) and helps deliver cleaner, healthier air throughout the building.
Yes. Steril-Aire UVC systems are specifically designed for installation within HVAC equipment. The UVC light is contained inside the air handling unit, so there is no exposure risk to building occupants or maintenance staff. All devices meet recognised safety and electrical standards for Australian mechanical services applications.
Cleaning time depends on the level of contamination, but most coils show visible improvement within 30 to 90 days of installation. During this period, Steril-Aire’s high-output UVC energy penetrates the coil depth, removing biofilm and organic buildup that restrict airflow and heat transfer.

Field data shows that Steril-Aire UVC can achieve:

  • AHU Total 84
  • Pressure Drop Average  18.89%
  • Heat Transfer Average   36.10%
  • Airflow Average 12.73%

These improvements translate to measurable reductions in fan, compressor, and pump energy consumption — helping buildings lower operating costs and improve NABERS and Green Star performance ratings

Absolutely. Mould and odours originate from microbial growth within coils and drain pans. Steril-Aire UVC destroys mould spores and organic residue, preventing regrowth and eliminating odours at their source. This keeps HVAC systems hygienic and odour-free without the need for chemical cleaning.
Yes. Steril-Aire UVC supports AS1668.2 ventilation requirements by improving air cleanliness and enabling potential reductions in outdoor air rates, which can reduce energy use. It also aligns with ASHRAE 241-2023, helping deliver higher “equivalent clean air” to reduce the risk of airborne disease transmission in indoor environments.
Steril-Aire pioneered high-output UVC for HVAC systems and remains the global benchmark for germicidal performance. Independent testing confirms that Steril-Aire produces up to 6 times the output of conventional UVC devices in HVAC operating conditions (10°C, 2 m/s air velocity) at end of life, ensuring consistent microbial control and measurable efficiency gains.

Steril-Aire UVC is widely installed across hospitals, laboratories, universities, aged care, offices, retail, and food processing facilities. It’s trusted by building engineers and facility managers seeking proven HVAC hygiene, IAQ improvement, and energy efficiency results throughout Australia and New Zealand.

Steril-Aire UVC perpetually cleans coils , drain pans and other surfaces eliminating manual coil and drain pan cleaning and chemical use as well as reducing duct cleaning and assisting with decreased corrosion.

Regular mechanical inspections and filter changes are still essential. The result is a cleaner, lower-maintenance HVAC system with longer component life and better long-term performance.

You can contact Steril-Aire Oceania for engineering support, technical data sheets, or specification assistance. We provide guidance for consultants and contractors to ensure correct UVC sizing, placement, and compliance with Australian standards. UVC Specification requirements click HERE

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