Are UV Lights the Answer to Your Indoor Air Quality Woes?
- December 15, 2014
Ultraviolet (UV) lights have been used for a number of years as a weapon against biological contaminants in the food industry and in medical settings. UV lights have grown in popularity as a means to combat microbes in the home environment as well. Ultraviolet germicidal irradiation (UVGI) air cleaners offer homeowners a strong solution for improving indoor air quality.
Airtight homes provide greater efficiency and comfort in regards to temperature, but they’re also the reason indoor air may be two to five times more polluted than the air outdoors, according to the U.S Environmental Protection Agency (EPA). This lack of ventilation and fresh air can cause the buildup of a variety of irritating and unhealthful particles.
Homeowners may use a variety of tactics for controlling pollutants at their source, but with biological contaminants such as viruses, bacteria, mold and fungus, more protection may be needed to assure the health of a home’s occupants. UV lights ensure that the microbes are destroyed.
What Are UV Lights?
UV light wavelength is longer than that of X-rays but shorter than that of visible light. UV light is present in sunlight, and we’re all familiar with the harm sunburns can do to the skin. UV light used in air-cleaning technology works by destroying the DNA of the organisms so that they cannot reproduce.
In the home setting, UV lights target organisms that may be airborne or that are found growing on surfaces, such as the air conditioner coil, in ducts or in condensate pans. UV lights perform particularly well when used to kill organisms growing under moist conditions, such as that found near the indoor coil. Most UV lights designed for residential use are low-pressure mercury vapor lamps, which emit UV radiation strong enough to kill microbes.
Types and Effectiveness of UVGI Lamps
Whole-house UVGI systems are designed to target either the organisms in the air as they’re drawn into the HVAC system or a specific area of the system where the organisms may be reproducing. The most common locations for the lamps within the system are upstream of the cooling coil and in the ducts, downstream of the filter.
Portable models are available, either to use in spot sterilization or to address a problem in a specific room in the house. Lamps are downstream of the filter in portable models.
High-output residential UVGI systems have been shown to be particularly effective at disinfecting or reducing vegetative bacteria, mold and viruses. Higher relative humidity can affect performance of UVGI light systems, as can air temperature.
Systems with bulbs that provide maximum performance at cooler temperatures can effectively check microbes that may flourish in moisture on indoor coils.
UVGI technology is considered most effective when it’s used in addition to mechanical filtration. Good quality filters with a minimum efficiency reporting value (MERV) of 5 to 8 can trap mold and spores, while filters rated 9 to 12 are able to trap Legionella. Filters rated over MERV 12 can capture bacteria. UV lights offer another layer of protection by treating the air that passes through the HVAC system.
What’s more, UVGI can help prevent a buildup of harmful organisms on the coil that may impede airflow. A layer of pollutants just two-thousandths of an inch thick can slow airflow by 9 percent and cause damage to the system.
Maintenance and Safety
UVGI lamps do require occasional cleaning, and the bulbs should be checked occasionally to make sure they’re burning brightly enough to be effective. Generally, they should be replaced once a year.
For more information on UV lights and how they can help improve indoor air quality, give us a call at Comfort Services Inc. We proudly serve Aberdeen, Southern Pines and surrounding communities.
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