Considering Using UV Lights to Improve Building IAQ? Here’s What You Need to Know

As important as efficient HVAC air filters are for improving your building’s indoor air quality, they can’t effectively control biological contaminants such as bacteria and viruses. Having UV lights installed in your heating and cooling system gives you an added layer of protection from these contaminants. To get the most out of a UV light system, though, there are a few things you should know.

How Light Can Purify Your Air

UV lights used for air purification are known as ultraviolet germicidal irradiation (UVGI) lamps. They’re installed inside the duct system of your heating and cooling system and shine ultraviolet light into the passing air and the contaminants carried in that air.

This light, the same wavelengths found in sunshine, damages the DNA of biological contaminants such as mold spores, viruses, and bacteria and prevents them from reproducing. Over time, the amount of these microbes in your building’s air drops, leaving you with cleaner, healthier air.

Among the microbes UV lights can sterilize are:

• Rhinoviruses (common colds)
• Influenza (flu)
• Streptococcal pharyngitis (strep throat)
• Staphylococcus aureus (MRSA infections)
• Mycobacterium tuberculosis
• Aspergillus and Penicillium (common mold species)

Because these lights do nothing against particles such as dust and pollen, you’ll still need an efficient HVAC air filter.

The Benefits of Improved Disinfection

UVGI lamps are tried and tested technology for cutting down on airborne microbes. They were first used in a hospital setting in the 1930s and are still common in hospitals, research labs, food processing facilities, and other locations where cleanliness is critical.

A commercial building with dozens or even hundreds of people passing through every day creates ideal conditions for disease to spread if the air quality isn’t carefully controlled. By keeping your building’s air cleaner, UV lights can help cut down on the spread of colds and flu, as well as symptoms experienced by those with allergies or asthma.

The potential benefits of a UVGI system include:

• Fewer lung-irritant and disease-causing biological contaminants in your air.
• Less risk of mold in your HVAC air ducts and air handler.
• Less musty or “smelly sock” odor caused by mold.

Research Before You Buy

Improving your indoor air quality with UV lights isn’t as simple as buying a system and sticking it in the building’s air ducts. Not all UVGI systems are equally effective. Cheaply made models may not have the intensity required to sufficiently reduce the contaminant load in your air. Ultraviolet light is most effective at destroying microbes when its intensity is between 260 to 265 nm. Anything much farther from that will require more exposure time to sterilize microbes.

Correct installation is critical. An incorrectly installed system might fail to direct light where it should, allowing microbes to pass unharmed. While correctly installed systems are safe as long as you take reasonable precautions, incorrectly installed systems put you at risk for serious UV damage to your eyes and skin.

To maintain your UV lights, you’ll only need to replace the bulb every one to three years, depending on the model. The bulbs lose efficiency with age, so change them on schedule. Occasional cleaning is also recommended.

A UVGI alone isn’t enough to ensure clean air. It’s only an additional line of defense against airborne microbes. Before you consider investing in UV lights, install a higher-efficiency air filter with MERV 5 to 11, bring your indoor humidity into a healthy range, and plan to have your HVAC system maintained annually.