For over 100 years, scientists have known that UV light can prevent the growth of bacteria and microorganisms. This has led to their widespread use in hospitals, water filtration systems, and in the food industry. It was only a matter of time before we started using UV light to improve indoor air quality. Today, we’re talking all about UV lights and their use in residential HVAC systems. Let’s dive in.

How do UV lights help improve air quality?

Our home HVAC systems don’t purify the air we breathe. Much of that air gets recirculated, and it often contains many pollutants. UV lights work to remove the following:

  1. Viruses and pathogens
  2. Mold or fungi
  3. Germs
  4. Dust
  5. Allergens
  6. Bacteria

Installing UV lights in your residential HVAC system is a great idea for anyone with kids, pets, or allergies. It’s also extremely beneficial to anyone living in a humid area that’s prone to mold growth.

How it works

Ultra violet light works to purify the air you breathe by capturing and destroying pollutants. The wavelength of ultraviolet light causes the DNA of these pollutants to break down. This prevents them from replicating, and they eventually die. As air passes through the chamber with UV light bulbs, it gets purified.

Types of UV light for residential HVAC systems

There are two options for ultra violet lights with your HVAC system: Air Sterilization and Coil Sterilization. Let’s look at how these work.

With Air Sterilization, moving air gets purified by a complete UV light unit that’s installed in the return air duct of your HVAC system. It cycles on with the air handler blower. With Coil Sterilization, a UV light unit is also installed in the return air duct of your HVAC system. For instance, this light is shaped like a stick so it purifies the air handler coil. This coil sterilization system runs at all times. Coil Sterilization is the most reasonably priced of our two options. It’s also the most common type of UV light for home HVAC systems.


The most important factor determining the effectiveness of your ultra violet light is its placement. The UV lights need to be mounted adjacent to the evaporator or cooling coil. They need to be on the downstream side of the coil, which is the cold air side. The ultra violet lights need to shine on the cooling coil, as well as the water drain pan beneath the coil. This is because wherever there’s water, there’s potential for the growth of mold spores. Shining UV lights at the water drain pan eliminates these particles from entering the air you breathe. For instance, if your UV lights are mounted somewhere else, mold and bacteria can spread throughout your HVAC system. As a result, your air will be contaminated.

In Conclusion

When installed properly, ultra violet lights in residential HVAC systems sanitize indoor air. They can help prevent the spread of colds, viruses, and other bacteria. So considering our current concerns with COVID-19, air purification systems are especially important to consider these days.

Do you have questions about UV lights for your home HVAC system? Our skilled technicians at K&S have the answers. ​Schedule your appointment online or give us a call. You can reach us at (507) 282-4328 for our Rochester location, and (952) 697-4328 for our Twin Cities location.