If you have ever had an HVAC replacement or cleaning, the HVAC technician or air duct cleaner may have asked if you’d like UV lights installed inside your HVAC. They claim this will prevent mold and mildew from getting into your home, and of course you don’t want that gunk in your space. But can a lighting system really help ease these concerns? Such an add-on certainly sounds like a gimmick, so is there any science to support the claim or is it just an empty promise?

Air Pros will help separate fact from fiction with answers to these common questions about UV lights for HVAC systems.

Question: Are mold and bacteria a concern in HVAC systems?

Fact: Yes, it is scientifically proven. Fungal contamination in HVAC units is a widespread issue that shouldn’t be ignored. This contamination often contributes to building-related diseases, like infectious diseases, allergic rhinitis, asthma and hypersensitivity pneumonitis, according to the National Center for Biotechnology Information. But Ultraviolet (UV) lights can be used in a variety of applications, including air purification. The UV light can help eliminate many types of fungi, bacteria, germs, viruses and pathogens.

Question: Will UV lights really increase the air quality in my home?

Fact: Yes, your home is susceptible to fungus. In 1996, an NCBI study installed UV lights on certain floors (and not on others) of an office building for four months to measure and compare the fungal levels of each floor.

  • UV lights reduced fungal contamination within air-handling units.
  • UV lights reduced levels of fungal contamination in the fiberglass insulation.
  • UV lights reduced levels of airborne fungi in the floor space.

In 2012, researchers at Duke University Medical Center used ultraviolet radiation to nearly eliminate drug-resistant bacteria in 50 hospital rooms, reducing the number of bacteria by more than 97 percent. Many factors play a part in the effectiveness of a UV light in your home’s HVAC system, so it needs to be done methodically.


Question: Can a UV light installation still be a waste of money?

Fact: Yes, so make sure your home conditions are right and installation is completed correctly. It’s important to hire a trusted HVAC technician. These factors can contribute to the effectiveness of UV lighting, according to the National Air Duct Cleaners Association:

  • Intensity and number of UV lamps.
  • Placement and direction of UV lamps.
  • Surrounding temperature and humidity levels of home.
  • Reflectivity of surrounding surfaces.

With the right conditions and proper installation, UV lights are very effective at killing viruses, mold, fungi and bacteria, keeping them out of your home. Who knew adding an HVAC UV Light benefits the home so much.

Conventional air conditioner filters are fine for reducing the amount of larger inorganic particles that infiltrate your ductwork. However, too often smaller living microorganisms called bioaerosols slip through your standard filtration media and escape into your household’s indoor air environment. In addition to this infiltration of bioaerosols like mold spores, bacteria and mildew, other common airborne pollutants such as dust mites, secondhand smoke, pet dander, and dangerous gases such as radon and carbon monoxide can be found in your home. All of these contaminants create poor indoor air quality that can significantly affect your health and trigger allergies and respiratory problems. One tactic for neutralizing some of these pests has been found to be helpful is ultraviolet germicidal irradiation technology, or UV lights.

For years UV lights have been utilized in clinics and hospitals to keep both air and medical surfaces clean and disinfected. While they might not be a cure-all for all of your poor indoor air quality problems, studies show they are effective at eliminating organic pollutants such as mold, mildew, fungus, bacteria and viruses in HVAC ducts and in air handling units where moist conditions may prevail. These types of microorganisms may be especially prevalent in Arizona, where most people keep their windows and doors tightly shut in the hot and humid days of summer. To free your ductwork and your indoor environment of breeding pollutants, UV lights can be installed throughout the ducts and near the evaporator coil. These lights are focused on traveling microorganisms, and kill them as they circulate through your air conditioning equipment.

Some air treatment systems are also installed with photocatalytic reactors, which, when activated by the ultraviolet light, can reduce volatile organic compounds (VOCs), the compounds released from chemicals, fumes and vapors found in building materials, furniture, solvents and the like.

How a system utilizing UV light technology works:
1. An HVAC professional will install a single or dual UV lamp within your ductwork or near your evaporator coil (the coil that is inside your home). This UV lamp emits a continual germicidal light on all of the indoor air that flows through your ductwork.
2. This UV light is capable of penetrating the DNA of microorganisms like mold and disrupting their reproduction cycles, leading to germ elimination.
3. Because an efficient cooling system circulates a household’s worth of air throughout your home several times a day, your indoor air will receive a constant disinfection treatment by the installed UV lights. After just the first 45 minutes of ultraviolet light treatment, as much as 50 percent of the bioaersols in your home may be destroyed.
4. Because ultraviolet lights function on wavelength and don’t disperse aerosols, homeowners know they are safely sterilizing their indoor air environment without releasing dangerous ozone that can affect indoor air quality. Many aerosols contain materials capable of triggering and causing allergy and respiratory problems, making UV lights the more human-friendly solution.

To learn more about how UV lights can significantly improve the indoor air quality in your Tucson home, or to learn about other high-quality heating and cooling products and services, contact your local HVAC experts at Air Pros.

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