One of the safest ways to lower harmful and possibly allergic organic substances in your home is with UV lights. When placed inside the HVAC system, these lights will reduce populations of bioaerosols that include mold spores, viruses and bacteria and dust mites. The combination of warm temperatures and humidity help these organisms thrive indoors year-round.
What Are UV Lights?
Ultraviolet light has the same wavelength as the UV light coming from the sun. Sunshine is a natural disinfectant because of this wavelength. These lights have been used since the early 1900s to clean air in medical, daycare and food service settings. The UV portion of light changes the DNA and RNA of thin-celled organisms, rendering them sterile. Since they can’t reproduce, the lights are a chemical-free way to create healthier indoor air.
While disinfectants are readily available for cleaning your home, some create hazardous volatile organic compounds (VOCs) that can have mild to serious side effects. These cleaners work primarily on solid surfaces and don’t lower the population of bioaerosols throughout your home’s air.
Spray disinfectants don’t stay airborne long and also contain VOCs. Infectious and irritating particles will still float through your home’s air, eventually landing on the floors and furniture where they can harm anyone who unknowingly ingests them.
Placing the Lights Inside the HVAC System
When UV lights are placed inside an HVAC system, they sterilize all the organic particles that pass by them. UV light can damage eyesight, making this placement one of the safest. HVAC contractors can place them strategically inside the ducts, as well as pointing them inside the air handler at the evaporator coil. This coil carries the cold refrigerant from your air conditioner. As the air passes over it, the refrigerant absorbs the heat in the air, cooling it.
The humidity in your home’s air also condenses on the coil. It collects in the drain pan below the coil and drains away via the drainpipe. This condensation creates an ideal environment for mold and biofilm growth on the evaporator coil and pan. When it does, your cooling system’s efficiency is reduced and your indoor air quality falls.
A biofilm that’s just 0.002 inches thick—about the same size of the diameter of a human hair—can reduce cooling efficiency by nearly 10 percent. Cleaning will remove the mold or biofilm, while UV lights stop it from growing altogether. Keeping the coil clean also helps prevent the coil from freezing, which can damage the compressor and drive up energy costs. Given the excessive humidity in our region, it’s important to keep the coil as clean as possible for effective dehumidification in the summer.
Managing Indoor Mold
While the air handler poses an ideal environment for mold growth without UV lights, other places in your home are, as well. Places like bathrooms, kitchens and basements routinely have enough humidity throughout the year to support mold growth.
Mold is nature’s way of breaking down organic materials and it’s found nearly every place on earth. While it’s indispensable outdoors, inside your home, it can rot wood, drywall and anything made from wood and fabric. Some people have a high level of sensitivity to the spores that can make them physically ill, especially if their immune systems are suppressed, have allergies or an underlying lung disease.
Mold and mildew will decompose the structure of your home and create offensive odors indoors. Since homes are heated in the winter, it’s a year-round problem that may even be hidden from view inside walls and floors where any plumbing leaks occur or moisture condenses, including the attic insulation.
Problems Associated With Bacteria and Viruses
UV lights can help reduce the likelihood of infection from bacteria and viruses that may be prevalent from the fall through the spring. When the humidity drops in the fall, the spread of colds and the flu increase. As air dries out, the coating around bacterial and viral cells evaporates, which makes them penetrate your respiratory tissues faster. Sneezing sends thousands of droplets into the air that can infect others. When the droplets pass by a UV light, they can no longer reproduce, eliminating the potential hazards for contacting a contagious disease.
If you’re concerned about eliminating more than the bioaerosols in your home, consider using UV lights combined with other air filtration technology, like HEPA (high efficiency particulate air) filters. These units are available as portable devices or as whole-house filtration systems installed in the HVAC system. A HEPA filter traps 99.99 percent of all particles 0.3 microns and larger. Between particle entrapment and genetic alteration, your home’s air quality will be exceptionally high.
One of the biggest benefits of combining UV lights with HEPA filtration is reducing the dust mite population inside your home. Dust mites live in nearly every home, and by themselves, they don’t pose a danger for human health. The mites feed on the dead skin cells pets and people shed daily. However, some people have an allergy to dust mite waste. Controlling their populations is possible with disciplined and routine cleaning, along with UV lights and high efficiency filtration. The mites and their waste are microscopic, but large enough to become trapped in a HEPA filter.
When forced air HVAC equipment runs, all the air in your home can pass through the ductwork as many as 75 times per day. If you keep the fan running continuously, it may pass through the system 150 times each day, giving you an effortless way to manage the dust mite population in your home, along with the mold, bacteria and viruses.
HEPA filtration systems need to be installed by an HVAC contractor since the filters slow the airflow through the system. These filters achieve such efficiency because they’re thicker than the standard HVAC air filter. If they’re placed in a system without a boost to the airflow, they can result in premature system failure and high energy costs.
Once the HVAC contractor has set the UV lighting system up in your home’s air handler and ductwork, you’ll have to periodically maintain it. After about a year, the bulbs lose some of their effectiveness and will need to be replaced to maintain the protections the UV lights give you. Since an HVAC system should be professionally maintained each year to keep energy bills low and increase the system’s lifetime, an HVAC contractor can easily replace the bulbs.
Keeping the air filter clean also improves the performance of UV lights. Dust enters the air handler when the filter is dirty and can cover the bulbs, lowering the amount of UV light cast inside the system. If you opt for a whole-house HEPA filtration system with UV lights, you’ll have to change the filter annually, as well, depending on the airborne particulate load in your home.
To learn more about the benefits of UV lights for your health, comfort and energy bills, contact Griffith Energy Services. We’ve provided outstanding HVAC services for homeowners in Frederick, Baltimore and Manassas, as well as surrounding areas, for more than 100 years.
Written by Kevin Spain