UV Lights and Indoor Air Quality: Understanding the Science

January 18, 2024
IAQ in Roseville, MI

If you’re searching for an effective solution for improving your home’s air quality, installing HVAC UV lights is a good choice. Although some UV light units can be somewhat expensive, installing one in your home will provide major benefits and help keep your family healthy. Read on to learn about how UV lights work, how they can improve indoor air quality and the other benefits they can provide.

What Effect Do UV Lights Have on Indoor Air Quality?

Germicidal UV lights can be installed inside any existing HVAC system, and they work to prevent the system from circulating bacteria, viruses and mold spores around the house. All microorganisms are vulnerable to ultraviolet light, especially shorter wavelength UV-C light. When bacteria and other microorganisms are directly exposed to UV-C light, it drastically alters their DNA. Specifically, UV light damages the nucleic acid inside of the cells, which “deactivates” the organism’s DNA so that it can no longer multiply and cause an infection. When the organism tries to multiply or replicate after being exposed to UV light, it instantly dies.

UV light is an extremely effective germicide, which is why it’s often used in water treatment and purification, food processing and many medical applications. It is also a great option for improving indoor air quality since it will destroy any bacteria and viruses as they circulate through the HVAC system. HVAC UV lights will generally never be able to kill 100% of the mold, bacteria and viruses in a home, but they are still extremely effective. Studies have shown that UV lights will typically eliminate around 97% of mold and bacteria in a building and more than 90% of viruses like influenza.

Types of Germicidal UV Lights and How to Know Which One Is Best

There are two different types of germicidal UV light units available for residential HVAC systems: air-sanitizing lights and coil-sanitizing lights. Both are designed to eliminate mold and harmful pathogens, but each one serves a slightly different purpose.

In central air conditioning systems, condensation continually forms on the evaporator coil inside the air handle chamber. The condensation combined with the warm air flowing over the coil creates the perfect conditions for bacteria and mold growth. As the air conditioning runs, lots of mold spores and bacteria then get spread around the home, worsening the indoor air quality. Coil-sanitizing UV lights are designed to prevent this issue and will destroy any mold and bacteria on the coil and also prevent them from returning. A coil-sanitizing UV light unit mounts inside the air handler so that the UV rays shine directly on the entire evaporator coil. This type of UV light unit is designed to remain on 24 hours a day from spring to fall or however long the AC system is in use to ensure no mold and bacteria can ever start growing.

Air-sanitizing UV light units are usually installed in either the return plenum just before the air handler or the supply plenum where the cold air from the AC and hot air from the heating system flows out. However, the unit can normally also be installed in the air handler or in any main supply or return air duct. While coil-sanitizing lights will mostly just destroy bacteria and mold on the evaporator coil, air-sanitizing lights will eliminate pathogens and mold spores from the air circulating through the ducts. If there is any mold growing inside on the walls of the duct, the UV lights will also instantly destroy it. This makes a coil-sanitizing unit ideal if you have any part of your duct system where condensation forms, as the UV lights will ensure mold can’t start growing and spreading.

Air-sanitizing UV lights are usually slightly bigger and more powerful than coil-sanitizing units, which is important for ensuring that all of the air flowing through the duct is exposed to the UV rays. Another difference is that air-sanitizing lights don’t remain on constantly and instead are wired so that they turn on and off alongside the HVAC system. This means that air-sanitizing lights will contribute to better indoor air quality all year long when your air conditioning or heating is running instead of only during the hotter months when you’re using your AC.

If you’re also concerned about airborne allergens and pollutants in your home and not just about eliminating mold, bacteria and viruses, you may want to consider installing a whole-home air purification system. Some of these air purification systems have UV lights inside them as well as highly-efficient filters that will eliminate the majority of allergens and pollutants from the air as it moves through your ductwork. However, even with whole-home air purification, you may still want to have a coil-sanitizing light unit installed as well to keep your AC evaporator coil clean.

Benefits of Installing UV Lights In Your Home

The biggest benefit of installing germicidal UV lights in your HVAC system is to improve air quality and keep you and your family healthy. If anyone in your house is ill, the UV lights will lessen the risk of everyone else getting sick by preventing the bacteria or viruses from spreading into every room.

One thing many people don’t realize is that UV lights can also improve the effectiveness and energy efficiency of central air conditioning systems. If you don’t have a coil-sanitizing light in your air handler, lots of mold and bacteria will continue building up on the evaporator coil. Mold growth is an especially big issue, as it can essentially start to insulate the evaporator coil and prevent as much air from directly coming into contact with the coil. This makes the heat transfer process less effective and reduces how much heat the evaporator coil and refrigerant can absorb from the air. Some studies have shown that this issue has the potential to eventually reduce the effectiveness of an AC system by up to 35%. As a result, your AC will cool much more slowly and use lots of additional energy.

Another benefit to installing UV lights in your HVAC system is that they can help keep the air in your home smelling cleaner and fresher. When there is lots of bacteria and mold growth on the evaporator coil or mold is growing in your ductwork, it will cause the air flowing out of your vents to smell moldy and musty. Even if you have the evaporator coil cleaned every year, you will still often end up with your AC starting to smell musty. By installing a UV light unit, this is an issue you’ll no longer need to worry about.

If you need help improving the air quality in your home, you can count on C & C Heating & Air Conditioning. We install UV light units as well as air purification systems and whole-home humidifiers for residents of Roseville and the Detroit Metro area. We also offer professional air duct cleaning services, which is another great way to boost the air quality in your home. If you need any heating or cooling repair, maintenance or installation services, our certified technicians can take care of all of your HVAC needs as well. For more information on our UV light installation services, give us a call today.

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