Indoor air quality is a growing concern for homeowners and businesses alike, especially as people spend more time indoors. One innovative solution gaining popularity is the use of UV light for HVAC systems, including air conditioners. These specialized lights are designed to kill bacteria, mold, and viruses, improving both air quality and the HVAC system efficiency. But how effective are they, and are they worth the investment? In this article, we’ll dive into the science behind UV light technology, explore its benefits for HVAC systems, and address common questions about its effectiveness, installation, and maintenance.
What is UV Light?
UV is short for ultraviolet. The UV light is an invisible electromagnetic radiation within the band between visible light and X-rays. There are three main types: A, B, and C, which vary according to their wavelength.
How UV Light Kills Microorganisms
The UV radiation, especially UV-C, has another significant germicidal effect: the ability to damage DNA and RNA.
In some cases, the damage is severe enough that cells die. For microorganisms like mold, viruses, and bacteria, this is a death sentence. In other cases, the microorganisms fail to replicate and reproduce.
This property makes UV lights an excellent choice for sterilization.
UV Light in HVAC
For its sanitizing property, HVAC systems frequently include UV-C lamps. It is often installed in the evaporator coil for coil sterilization or return air ducts for air sterilization.
Since the UV radiation can reduce allergens and pathogens in the air stream, they are now increasingly getting popular. And, the process is chemical-free. The air doesn’t have the chance to get polluted either.
However, exposure, intensity, and airflow rate always determine the effectiveness of UV lights.
Benefits of UV Lights for HVAC Systems
We have already mentioned, the main goal of UV light in the HVAC system is sanitization. The light is often installed in the coil or ducts to disinfect the parts directly or the air passing through them. It yields to the following benefits:
1. Improved Indoor Air Quality
Because of the breaking down of the DNA and RNA of bacteria, viruses, and mold spores, these contaminants can’t survive in the presence of UV lights.
These contaminants pollute the air just by existing in it. They often come from outside and get into the indoor air if left untreated. Usually, we require additional treatments or purifiers to get rid of these pollutants.
UV lights work as an all-in-one solution for these types of impurities.
Since the air gets more pure, the inhabitants are less prone to illness. If they have allergies and asthma symptoms, those get reduced significantly too.
2. Odor Reduction
Bacteria and mold are some of the common sources of foul odors in the HVAC system and indoor air. By breaking down these particles, the UV light directly reduces odor.
Some Volatile Organic Compounds (VOCs) are also common indoor odor sources. UV-C light, combined with catalyst presence, breaks down these compounds too. The VOCs then turn into less harmful and odorless particles like carbon dioxide and water vapor.
3. Enhanced HVAC System Efficiency
HVAC systems are prone to moisture. This is especially true for evaporator coils in the air conditioning system. The moisture leads to mold growth and bacteria buildup.
The microbial buildup causes interruption of the airflow and heat transfer.
By installing UV lights, you can make sure that these buildups don’t happen in the first place. So, the airflow remains strong, and heat transfer becomes easier. The improved airflow also distributes the conditioned air more effectively.
With good airflow, components like fans don’t need to work hard. The HVAC system can refocus and save its energy while functioning. So, the UV light indirectly leads to lower energy bills too.
4. Reduced Maintenance and Longer Lifespan
Since the mold and bacteria growth from moisture is reduced by UV lights, the overall pressure on the HVAC system gets reduced significantly.
That means the HVAC system can run efficiently for longer periods. So, the UV lights make the system have a longer lifespan.
With lower strain on the system, you don’t run the risk of overwork. Combining this with the lower frequency of coil and drain line cleaning (because buildups are prevented), the HVAC system doesn’t require treatments as frequently.
Effectiveness of HVAC UV Lights
UV lights are a valuable tool for indoor air quality and HVAC efficiency. However, they aren’t a standalone solution.
Studies like PMC and MDPI have shown that UVGI (Ultraviolet Germicidal Irradiation) significantly reduces, if not eliminates, fungal contamination in air handling units. So, it is a good sterilizing agent for spaces where air quality is crucial, like hospitals.
However, the UV light technology is not without its limitations.
How Effective is UV Light in HVAC Systems?
First, the light is only effective against organisms that contain DNA and RNA. So, inorganic contaminant particles like dust and debris are not affected by UV lights. Besides, these particles sometimes shield the microorganisms from exposure too. As a result, some microbes are not intercepted by the light’s radiation.
Long exposure to UV lights often degrades the quality of the HVAC materials too. This is often the case where proper shielding of components hasn’t been used. Inaccurate exposure can harm the human eye and skin too.
Factors Affecting Effectiveness
- Intensity and Wavelength
Higher intensity and wavelength range is more effective for the UV light range.
Intensity is the amount of UV lights emitted. Higher intensity lights expose more UV rays to the particles and thus have higher effectiveness. Even with the same intensity, some factors like distance between the source and particle, age of the bulb, etc. can affect the effectiveness.
For wavelength, 254 nanometer is considered to be the sweet spot. It has the maximum damaging effect on microorganisms.
- Exposure Time
The UV light needs a certain time period to destroy the virus, bacteria, mold, fungi, etc. If they pass before that, the UV light’s effectiveness becomes less visible. Usually, this happens when the air flows faster.
The “dose” is also measured with the combination of intensity and exposure time. As the “dose” increases, so does the light’s effectiveness.
- System Design and Placement
Coil sanitizing lights are placed in the evaporator coil to prevent microbial growth. Air sanitizing UV lights are usually located in the ductwork to tackle the airborne particles. Placing them in their respective places yields the most result.
If the light is also placed in such a way that HVAC components create a “shadow effect” on the particles, then the UV light won’t be as effective.
- Cleanliness of the System
Dust and debris within the air and HVAC components also “shield” the microorganisms and create the shadow effect.
Clean coil and ductwork don’t have this problem. If you have high-quality air filters, they can filter out the non-organic particles effectively too. As a result, the pathogens get exposed to the light.
- Type of Microorganism
Different microorganisms have different strengths of sustainability in UV lights.
Different viruses and bacteria exhibit varying levels of vulnerability to particular wavelengths and intensities. In case of mold spores, they often need higher doses to get treated.
This may result in incomplete elimination of all the microorganisms.
- Airflow
If the air speed is high, the particles pass fast. This might mean the particles aren’t exposed long enough in the light to be effective.
The same applies to air turbulence. Smoother airflow means the particles pass down easily in a singular motion (less exposure). With turbulent air, more air and particles will come in contact with the light and more sanitized the air will be.
Maintenance Requirements of UV Lights
The UV lamps or light systems have bulbs in them that emit the UV light. However, these UV bulbs are prone to damage and degradation over time. Consider following these tips to maintain the bulb and the overall UV light systems:
- Replace bulbs periodically. Usually, UV light bulbs have a lifespan around 9000 hours. Change it within 1-2 years of continuous use.
- Wipe bulbs with a dry cloth to remove dust. The accumulation on the bulb reduces the effectiveness otherwise. Don’t use harsh chemicals to clean the bulbs and always disconnect power before cleaning.
- Check for signs of damage and malfunction periodically.
- Check for loose connections, components, or unusual noises from time to time.
- Conduct professional servicing annually. Take HVAC checkups and services from professional HVAC technicians, they usually include checking on air purifying solutions like UV lights too.
Safety Precautions
UV lights are harmful for all living cells, not just bacteria and viruses. Although the effect isn’t as quick and visible in larger lifeforms like us. However, they can still harm the skin and eyes and can cause other diseases when exposed long enough.
So, take the following safety precautions while running and working with UV lights:
- Avoid direct exposure and ensure proper shielding from the UV light contacts.
- Turn off the power before attempting any repair or maintenance.
- Follow electrical safety codes and guidelines while working with the kit. Always consult a professional if you are hesitant with electrical components.
- Some UV lamps can produce ozone. Some are even designed to prevent ozone creation. Pick one to reduce the ozone production as much as possible.
- Prolonged exposure of UV lights can damage materials like plastic and rubber too. Make sure to pick a lamp that is suited with the material of your HVAC system.
- Shield sensitive material in your HVAC system so that they aren’t in direct contact with the UV lights.
- Make sure the UV light system has the warning label. This will indicate the potential hazard to others.
- Consider getting a light system with Interlock Switches. The feature automatically turns off the Ultraviolet lights when a panel is open for maintenance.
Conclusion
UV lights are a powerful tool to target pathogens like bacteria, mold, and viruses. By doing so, it provides a cleaner HVAC system, a healthier environment indoors for your home or business. Besides, it is an effective way to improve system efficiency, extend the lifespan of it as a byproduct.
Despite the slightly higher initial price, the long-term advantages make it a sound investment. If you are considering adding UV lights to your HVAC system, consult with a professional to ensure proper sizing and installation for the best result. Ready to take the next step? Contact an HVAC specialist today to explore your options and breathe easier tomorrow. For more details, call 972-992-5006.
