UV Purification kills bacteria and viruses through direct contact with ultraviolet waves (UV). When appropriately installed within the ductwork of your HVAC system, it can reduce the growth and build-up of bacteria and viruses on the indoor coil—positively affecting the performance of your HVAC system and indoor air quality (IAQ).
How does UV purification work?
UV rays kill micro-organisms through direct contact. Each organism has a different exposure threshold required for the UV rays to kill it. Most organisms need to have exposure of about 20-30 seconds. The air flowing through your ductwork moves up to 2,000 cubic feet per minute (cfm). Therefore, any microbial organisms that are airborne won't necessarily get killed. However, this does not make UV purification useless because the UV light shines on the indoor coil. The indoor coil generates condensation, creating a moist, humid environment as your HVAC system operates (like a cold cup of water on a hot summer day). This dark, moist area is an optimal breeding ground for thriving micro-organisms. Microbial growth on your coil can have a few damaging effects on your IAQ and HVAC system:
It can block your coil, restricting the airflow and raising your system's static pressure.
It can cause foul smells from your HVAC system, known as dirty sock syndrome.
The bacterial growth can make its way into your home with the airflow
You will need to clean your indoor coils more often
Pros and cons of UV purification
Before adding UV purification to the IAQ arsenal, there are pros and cons to consider. Since UV purification kills microbial organisms by direct exposure to the UV rays, it will not necessarily kill airborne viruses and bacteria. It will, however, help prevent your indoor coil from microbial growth, which can help reduce odors and ensure your HVAC system works properly. Some UV purification produces a small amount of ozone, a known lung irritant. Therefore when purchasing a UV purification system, ensure it doesn't emit any ozone. UV purification works great in killing microbial organisms. However, it will not remove them from the airflow. For that, you will need effective filtration. Nonetheless, UV purification is an effective way to ensure your HVAC system stays clean from bacterial growth and will prevent unpleasant odors from your HVAC system.
The bottom line
UV purification is one of the ways to regulate the indoor air quality of your home. UV purification works by killing viruses, bacteria, and other micro-organisms through direct contact with the UV rays. UV rays kill most micro-organisms through direct exposure with the rays of about 20-30 seconds. For this reason, UV purification won't have a direct impact on the IAQ in your home. However, it will help prevent micro-organisms from growing on your indoor coil, which can cause foul odors, damage your HVAC system, and potentially make their way into your home.