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Debunking UGVI for HVAC&R at the time of pandemic


UVGI is an established means of disinfection and aims at preventing the spread of contagious and contaminated viruses. These are primarily designed for occupied rooms without any protective shield. 

Indoor Air Quality has become a significant aspect in today’s world, as it has a direct impact on the health of building occupants. A building must be qualitatively ventilated and the inside air must be free of micro organism for the health and well being of building occupants.

As we all have been witnessing the pandemic, so it’s vital now that we make sure that the air circulating inside the building must be free of microbes (Virus, Bacteria and Fungi). 

UVGI Technology (Ultraviolet Germicidal Irradiation) has been in use for so long for improving air quality as it enhances occupant health, comfort, and productivity. The role of air-conditioning and ventilation, in averting airborne infections has drawn extensive attention since the SARS outbreak. 


Ultraviolet Germicidal Irradiation (UVGI) is an air and surface disinfection method integrated with the HVAC system of the building. It uses ultraviolet (UV) light to kill or inactivate virus by disrupting and destroying its DNA, leaving it unable to perform their vital cellular functions. 

After using the HVAC system for many years, fungus growth starts inside all corners and joints of the ducts, which subsequently becomes a breeding ground for different kinds of bacteria and viruses. The regular deposit of microorganisms in the ducts and on the coils surface of AHU becomes an invisible health hazard.  It should be cleaned for a healthier environment.

UVGI is used as a safe alternative to manual or chemical cleaning for a cleaner inside of the HVAC system. As manual cleaning is cumbersome and leads to damage of the coils quite often. Chemical cleaning causes the chemical to remain inside the ducts and AHU coils which slowly come out in the form of minute droplets and vapors when the system is in working condition causing the inhabitants to inhale the same.

Application of UVGI

The UV lamps can be installed in AHU & Ducts. In AHU’s the installation is done near the coil surface so that the coil remains clean of virus and other micro organisms. For Duct based system, the installation is done inside the duct. The standalone units are also available for the area which does not have access to Centralized Air Conditioning systems. 


The effectiveness of UVGI has been proved by various international studies and research as the technology is in use since 1930. The UVGI Technology is meant primarily for air and water disinfection. With the advent of COVID, the UV lamps are used for air and surface disinfection. Since air is circulated through HVAC inside any building premises, it is necessary to have an active UV lamps integration inside the AHU & the Ducts to make sure that there is no air contamination for the health of building occupants.

How does UVGI work?

Ultra-violet (UV) energy kills or inactivates micro organisms (Viruses, Bacteria, and Fungi etc.). UV energy attacks the DNA of the micro organism by penetrating inside the cell membrane, breaking the DNA structure of the micro-organism and making it not to reproduce any further. Hence, the UVGI system inhibits the growth of any sort of micro organisms inside the duct lining or on the coil surface for the health of building occupants.

Low pressure mercury vapour lamps radiate about 95 percent of their energy at a wavelength of 253.7nm, which is close to the DNA absorption peak (260–265nm) which has a high germicidal effectiveness.

UVGI inactivates micro-organisms by damaging the structure of nucleic acids and proteins at the molecular level, making them incapable of reproducing.  DNA (De oxy ribonucleic acid) is critical for the growth of any viruses and other micro organisms.  UV photons irradiated by UV lamps can damage DNA in a variety of ways, resulting in the organism’s inability to replicate or even its death. An organism that cannot reproduce is no longer capable of causing disease. UVGI effectiveness depends primarily on the UV Dosage delivered to the micro-organism.

Component of the UVGI system

The main components of the UVGI system are UV lamps, Ballast, Parabolic Reflector and alloy metal framing for holding the structure. The life span of UV lamps is 9000 hours to 12000 hours.  High-efficiency UV ballast enclosed within IP54 rated enclosure to make sure there is no damage to control panel for efficient working of the system. Automation Kit for a live display of UV Lamp Indicator, Running Hour, Intensity meter.

Benefits of UVGI 

Improved Air Quality

It has been proved by various researches worldwide that UV lamps can improve the air quality as it has an effective killing against every sort of Bacteria, Viruses & Fungi when exposed to desired UV dosage. . The United States General Services Administration requires that UVC be included in cooling coils of air-handling units for all federal facilities and to maintain coil cleanliness and improve air quality. Eliminates growth of MOLD and MILDEW on cooling coil.

Improved heat transfer between chilled water in coils and air.

Improved air flow through coils.

Eliminates Microbial Load (Bacteria and Virus) passing through Air by deactivating /damaging it’s RNA/DNA

Improves Indoor Air Quality (IAQ) upwards of 70 percent.

Energy Saving

UV Lamps can help in Energy Savings for HVAC system through fan energy savings and cooling energy savings and significantly increases the life time of the coil. On average, UVGI results in net savings/ efficiency improvement of anywhere between 10 to 15 percent of the HVAC energy costs in a typical system.

AHU Maintenance savings

AHU coil cleaning is a major problem in HVAC maintenance. It is very difficult to do coil cleaning manually and this can be easily achieved by a safe alternative UVGI. Prevents periodic cleaning of coils, thereby significantly reducing maintenance costs. Also, the chemical cleaning is harmful as the left out chemical when come out with the air causes health hazards. 

Increased life of HEPA Filters

With UV Lamps installation, the life of HEPA filets get increased as the load of micro organisms become minimal as the UV Lamps take charge of the killing the virus then and there.

Green Building Benefits

UV lamps also help in achieving Green Building Benefits as there is no water wastage by cleaning the coils with jet pumps. Also, there is an energy saving happens as the fan and motor bear less load.


Extends the life of the equipment.

Low initial set up cost.

Compatible with new and existing HVAC systems.


Authored by

Hina Gupta

Operations, MG Cooling 


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