The use of UV light disinfection in HVAC systems has grown rapidly in recent years. Nonetheless, many people are still skeptical about whether UV lights work and have any noticeable effect on indoor air quality. The fact is that UV light is one of the most powerful disinfectants known to man. We’ll explain why it works and what options you have for adding UV lights to the HVAC system in your home or business.
Why UV Light Disinfection Is Effective
The first thing you need to understand is that ultraviolet light has three distinct wavelength ranges — UV-A, UV-B, and UV-C. Although the sun emits all three wavelengths of ultraviolet radiation, only UV-A and UV-B reach the Earth’s surface. That’s because the ozone layer blocks UV-C. In technical terms, what happens is that the oxygen molecules in the ozone layer absorb the UV-C light. This process causes the molecules to split into individual oxygen atoms that then react and combine with other atoms to create ozone (O3).
UV-A radiation is mostly harmless, but it can cause wrinkles, age spots, and other minor skin damage over time. UV-B radiation has more energy and causes some damage to DNA, which is the main reason why sun exposure can contribute to skin cancer. UV-B rays are also what causes your skin to tan under the sun and eventually get sunburnt. UV-C radiation has the most energy and is by far the most harmful since it quickly causes extreme DNA damage. The other issue is that nothing on Earth is used to being exposed to UV-C radiation since it never penetrates through the atmosphere.
The fact that UV-C light alters or damages DNA is what makes it so great at disinfecting and sterilizing. When microorganisms like bacteria, mold, fungal spores, or viruses are exposed to UV-C light, their DNA gets damaged in a way that renders them completely harmless. That means that they lose the ability to reproduce, spread, or cause infection. Some viruses have to be exposed to ultraviolet light for a bit longer before getting damaged and essentially destroyed, but bacteria and mold are damaged almost instantly.
How Coil-Sanitizing HVAC UV Lights Work
UV light disinfection is used in hospitals and labs to sanitize equipment and surfaces. Two types of UV lights are designed for use in central HVAC systems and work to prevent bacteria and mold from circulating around a building. The most common type is a coil-sanitizing light, which works to kill mold and bacteria on the evaporator coil in a central air conditioning system. This type of light is usually meant to stay on for 24 hours a day throughout the entire cooling season so that it also inhibits mold and bacterial growth.
A coil-sanitizing light works through UV-C rays shining straight down onto the evaporator coil and the drain pan underneath it. An AC evaporator coil and drain pan are always wet when the air conditioning system is running due to condensation naturally forming on the coil and then dripping down into the pan. This moisture combined with the warm air being drawn into the AC system can allow mold, algae, and bacteria to start growing. When these microorganisms are present, you’ll end up with the AC spreading mold spores and bacteria throughout the building and worsening the indoor air quality. This issue is why some buildings have issues with the air blowing out of HVAC vents having a musty, moldy odor when the AC system is running.
By installing a coil-sanitizing light, you should never have to worry about mold or bacteria in your air conditioning system. That means the air quality in your home or business will be better and you should never have issues with your air conditioning making your building smell moldy or musty.
Another advantage of a coil-sanitizing light is that it can help your air conditioning work more energy efficiently. That’s because mold growth on an evaporator coil interferes with an AC system’s ability to capture as much heat. Dust and debris also do the same, which is why it’s important to have your AC evaporator coil cleaned annually. This type of UV light can also reduce the chances of your AC’s condensate drain system clogging up by preventing mold and algae from growing in the drain pan and then getting washed down into the drain lines.
How Air-Sanitizing UV Lights Work
The second type of HVAC UV light is an air-sanitizing unit. As you can tell from the name, the purpose of this type of light is to destroy germs and mold spores in the air circulating through a central HVAC system. This type of unit is usually installed in the return or supply plenum, which are the large sections of ductwork on either side of the central HVAC air handler.
You can also install the light almost anywhere in the ductwork system if you have issues with mold growing inside any of your air ducts. While this will effectively kill the mold in that ductwork section, you’re much better off fixing whatever issue is leading to condensation forming inside your ducts and allowing mold to grow. That often means insulating the ducts, sealing up any leaks, or in some cases, completely replacing your ductwork system.
An air-sanitizing light is connected to the HVAC control board so that it automatically comes on and shuts off alongside the HVAC system. That means it will help eliminate germs and improve the air quality in your home or business throughout the entire year instead of only when you’re using your air conditioning like a coil-sanitizing light does.
As air flows through the section of ductwork where the UV light is located, ultraviolet radiation destroys many of the airborne microorganisms circulating through the HVAC system. Although some germs and mold spores will typically still end up passing through the light unharmed, it doesn’t take very long for the light to eliminate the majority of the microorganisms from the air in the building. That means you’ll be able to breathe easier and avoid your HVAC system spreading germs around the building and potentially making your family or employees sick.
With roots dating back to 1870, F.F. Hitchcock Plumbing, Heating & Cooling is the most experienced HVAC, plumbing, and electrical company in the Cheshire area. We serve residential and commercial customers, and you can count on our experienced, certified technicians to expertly handle your comfort needs. Whether you need a new furnace or air conditioning or your HVAC system needs to be repaired or serviced, you can trust our team to get the job done correctly. As the area’s leading indoor air quality service, we can also help if you want to install UV lights, a humidifier or dehumidifier or a purification system. You can also turn to us for your roofing needs or if you’re looking to add a solar power system to your building. For more information on the ways UV light disinfection can benefit your home or business or to schedule an appointment for any other service, contact us today.
