Not only is your HVAC system tasked with keeping your home comfortable year-round, but it also plays an instrumental role when it comes to your home's indoor air quality. A good-quality air filter can prevent a wide variety of pollutants from circulating in your home's indoor air, but it may not be enough for mold and other microbes that often trigger allergies and illnesses.
A little ultraviolet (UV) light can go a long way towards improving your home's indoor air quality, but is it worth the expense and effort of installing a UV germicidal lamp in your HVAC system?
How UV Light Tackles Mold and Microbial Growth
You may have heard the old saying "sunlight is the best disinfectant." Turns out it's true, but it's not the visible sunlight that does the work of destroying harmful bacteria and mold growth. The sun also produces ultraviolet light that's invisible to the human eye, and it's this light that plays a role in disinfection.
UV germicidal lamps reproduce ultraviolet light within the 280 to 200-nanometer wavelength spectrum. This particular wavelength, also known as UV-C, is capable of destroying microscopic organisms at the DNA level. When a microbial organism is exposed to UV-C, the radiation breaks apart the organism's DNA bonds. This leaves the organism too damaged to reproduce or otherwise function properly, resulting in the organism's eventual death.
For residential HVAC applications, UV germicidal lamps are usually installed within the indoor air handler plenum in close proximity to the evaporator coil. Multiple lamps may also be installed along the return air duct in an effort to sanitize incoming air.
Understanding the Effectiveness of UV Germicidal Lamps
Numerous studies have shown UV germicidal lamps to be exceptionally effective at improving indoor air quality by controlling infectious microorganisms. One study found that with optimal placement and exposure, UV germicidal lamps are capable of destroying harmful bacteria, viral aerosols, and other infectious microorganisms with a kill rate of 90 percent or higher.
Other studies have found UV germicidal lamps to be particularly effective at reducing symptoms related to sick-building syndrome. These lamps are also effective at controlling fungus growth that's responsible for a broad range of illnesses, including hypersensitivity pneumonitis and allergic rhinitis.
UV germicidal lamps have proven effective enough to be used in hospitals, industrial clean rooms, and other facilities where excellent indoor air quality is paramount. These lamps are often used in conjunction with HEPA filtration to ensure the highest possible indoor air quality.
Where UV Germicidal Lamps Fall Short
In spite of the benefits offered by UV germicidal lamps, there are several issues to consider that could make them less than ideal for your home's HVAC system:
- The effectiveness of UV light is a matter of time and intensity. Most organisms require ample exposure under UV light before being rendered harmless.
- Most UV germicidal lamps lack the intensity to disinfect moving air. Lamps with higher intensity are available, but usually at a higher cost.
- Exposure to UV light can also prove harmful to surrounding surfaces inside your HVAC system. UV light may cause plastic condensate drain pans and flexible ductwork to deteriorate in just a few years.
- Installing a system of UV germicidal lamps in your HVAC system may prove costly depending on the cost of parts and labor.
The overall effectiveness of UV germicidal lamps can be affected by a variety of different factors, including the number of lamps used; their intensity, placement, and direction; current temperature and humidity levels; and the overall reflectivity of nearby surfaces. These are important issues to consider if you're thinking about installing UV germicidal lamps in your HVAC system.
The Final Verdict
If you or a loved one constantly suffers from allergies and illnesses caused by mold or harmful microorganisms, installing a system of UV germicidal lamps in your HVAC system may be worth the time and effort spent. Otherwise, upgrading your current HVAC air filter and improving your home's fresh air ventilation could prove cheaper and more effective at improving your home's indoor air quality. For more information on your options, contact a company like One Hour Heating & Air Conditioning.