The idea of killing off the germs in your home just by shining a light into your air ducts admittedly sounds a little too good to be true, but HVAC U.V. lights really can improve your home’s air quality. In fact, these lights have been used for decades in hospitals and other facilities where sanitation is critical.
In fact, leading manufacturers of U.V. light systems have recently conducted independent studies that found U.V. light technology neutralizes and disinfects viruses such a COVID-19 with 99.99% effectiveness within 3 seconds of exposure.
Even so, purifying your home’s air with U.V. lights isn’t as simple as some manufacturers might make it seem and it’s important to research the options that are available.
How U.V. Lights Clean the Air
Ultraviolet (UV) lights for HVAC systems are also known as ultraviolet germicidal irradiation (UVGI) systems. They target a very specific type of air contaminant, namely microorganisms such as bacteria, viruses, and mold spores. You might be familiar with the way hanging laundry out in the sunshine helps kill any germs or mold clinging to it. U.V. lights work in conceptually the same way.
UVGI systems produce the same kind of ultraviolet light that’s present in sunshine, but at a much higher intensity than found in the sunshine that reaches the earth. This light destroys microorganisms’ nucleic acids, damaging their DNA and either killing them or leaving them unable to reproduce.
The light affects only living microorganisms, meaning these systems can’t control dust, pollen, pet dander or other particles that aren’t alive. High quality air filters are needed to remove these particulates from the air.
U.V. light’s ability to kill pathogens in water and air was scientifically proven early in the 20th century. These systems have been used in hospitals as far back as the 1930s to reduce the spread of diseases such as measles and tuberculosis.
They’re scientifically known to be effective against virus types such as rhinoviruses (common cold), influenza viruses (flu), and Severe Acute Respiratory Syndrome (SARS) and against bacteria such as Staphylococcus aureus (Staph infection) and Streptococcus variants.
The benefits are widely accepted and thousands of water treatment plants, major hospitals, and food handling facilities across the country use U.V. light systems as part of their efforts to minimize contamination.
Not All U.V. Light Systems Work the Same
All that said, cleaning your home’s air isn’t as simple as sticking any U.V. light system you can find into your HVAC ducts. To be killed or neutralized, microorganisms must be exposed to the right kind of light for the right amount of time. A U.V. system’s effectiveness in a given situation depends on several factors, including:
- Lamp wavelength and intensity
- Number of lamps
- Lamp position
In addition, before you start looking for an HVAC U.V. light system, you’ll need to review the two options available. It’s not uncommon to deploy both options in an HVAC system with a dual bulb system:
Coil Sterilization – This is the more common type. The U.V. light system is installed near the air conditioner’s indoor evaporator coil and shines constantly to prevent mold and bacteria from building up on or around the coil. Less mold and microbes on your coil means less bacteria in your air. Plus, the evaporator coil is a key component to the efficient operation of an A/C system. Keeping the coil clean greatly improves the ongoing operation of the A/C system over time.
Air Sterilization – Commonly referred to as “whole house” air purification, this system is specifically designed to kill microbes in your air. It’s installed in the return air duct. Because it purifies all the air passing through the airflow, it also reduces the risk of microbial buildup on your HVAC components, such as your air ducts, air filter, and drain pan.
When a U.V. Light System is Worth the Investment
While these systems do provide benefits, U.V. light systems are not cheap, and they require annual maintenance, which includes replacing the bulbs. The bulbs lose effectiveness over the course of 1-3 years (depending on bulb type) and eventually become ineffective at killing germs, even though they still produce visible light.
Before you invest in a U.V. light system, consider whether or not your household has indoor air quality needs that this air purification method can meet effectively. Or, perhaps you would like to be proactive and take a preventative approach to managing your indoor air quality at optimum levels.
If someone in your home is managing a respiratory condition, such as asthma, allergies or chronic obstructive pulmonary disease (COPD) or has a weakened immune system, any additional U.V. light system for air purification is likely beneficial.
In a humid climate such as South Florida, your evaporator coil is at a greater-than-average risk of getting wet and developing mold. A U.V. light system for coil sterilization reduces the amount of active mold spores on the coil and in the air.
U.V. light systems provide solid benefits in more crowded conditions with close exposure to others. Installing one of these systems might be a good idea if you have a large family in a small house or even if you enjoy filling your home with guests during the Fall and Winter holidays, which also happens to be the height of cold and flu season.
Because it controls a limited range of contaminants, a U.V. light system alone isn’t enough to keep your home’s air clean. You’ll still need a higher-efficiency air filter to trap the smaller particles of dust, pollen, and other pollutants that can aggravate allergies and asthma.
If you’re considering having an HVAC U.V. light installed, talk with a Quality First A/C technician first. They will be able to advise you on which type of system will do the best job of purifying your home’s air.