Some types of UV lights such as UV-C have been proven to kill germs and can thus be used in cleaning the air in the house by combining with the HVAC system. However, HVAC UV light damage is a risk to human beings and items in the home. Without the right precautions, you may even lose your sight from exposure to UV light.
Being directly exposed to the UV-C light used in HVAC systems is hazardous to the eyes and skin. Damage to the eyes can be both considerable and at times permanent. UV light can also damage solid items such as (non-stabilized) plastics and should thus be left to the experts for safety reasons.
What is UV light?
UV (ultraviolet) light is electromagnetic radiation within the 0 – 400 nanometer (nm) range. It’s found in tanning lamps, sunlight, mercury vapor lamps, cutting and welding arcs, and many other sources. The human eye cannot see UV light and it’s divided into the following wave ranges:
UV-A (400-315 nm) – Long-wave
UV-A light is the most abundant form of UV light and it causes wrinkles and tanning of the skin.
UV-B (315-280 nm) – Medium-wave
UV-B is one of the most dangerous forms of ultraviolet light and is responsible for skin cancer and skin reddening.
UV-C (280-200 nm) – Short-wave
UV-C is the best at controlling germs and other microorganisms susceptible to UV light. The ideal UV frequency for germicidal control is 253.7 nm.
UV (0-200 nm) – Vacuum UV
Below 200 nm, ultraviolet radiation can create ozone (O3).
From the above types of ultraviolet light, the best is UV-C and it shall be the focus of this article. Used right, UV-C can help control germs and clean the air. Without precautions, however, it’s quite dangerous.
UV light is used with HVAC systems in one of two ways:
Air sterilization: In-Duct UVC system
In this section of the HVAC system, ultraviolet light kills germs in the air as it passes through the system.
Ultraviolet Germicidal light (UVGi) is quite effective at killing off germs from the air and on surfaces. However, you’ll still need to filter the air for impurities since this light only kills the germs and doesn’t remove them from the air or surfaces.
Over the coil (coil sterilization)
The coil of your HVAC system is often warm and moist hence a breeding ground for germs, mold and mildew. UV light is thus more effective in this section of the HVAC system than elsewhere since it kills off the germs before they spread to the rest of the house.
Portable UV light system
With this option, you can always move the UV light to a location of your choosing to clean the air with it. This can be near a window or a section of the house prone to germs.
HVAC UV light damage
UV light used for air purification can damage people and items in the following ways:
While UV lights meant to kill germs (with UV-C) appear to produce very low light, they’re dangerous to the eyes. Direct exposure to UV-C light is dangerous and can cause severe and permanent eye damage.
If you must engage with the UV light in your HVAC system, you’re better off using UV protection such as goggles or glasses with a UV protective film. Other than that, an expert should handle the issue.
While UV-C isn’t the most dangerous form of ultraviolet light, direct and long-term exposure to it puts you at the risk of skin redness and cancer. A minute or so of exposure won’t do you any harm, however.
Damage on objects
UV light can damage plastics and other materials found in the HVAC system such as the flex duct and drain pan. Plastic can be stabilized to prevent damage from UV light but that’s an extra cost.
For this and other dangers of UV light, you should enlist the services of an expert to handle UV light or use protective gear. If you experience any discomfort after exposure to ultraviolet light, seek medical advice immediately.
Pros and cons of UV light in HVAC
There are clear benefits of using UV light in HVAC systems to purify the air since it kills off bacteria. However, there are downsides as well since it’s not the most effective method of killing germs from the air.
Pros of UV light in HVAC systems
Some HVAC UV light benefits include:
- UV light is 99% effective at killing bacteria and mold from the air in the right conditions.
- UV light kills most airborne mold, mildew, bacteria and other microorganisms.
- Uses less power than air purification HVAC systems.
- Air disinfection by UV light is enough to eliminate harmful airborne particles.
Cons of UV light in HVAC systems
The downsides to using UV light in HVAC systems include the following aspects:
- Can harm eyes, skin and objects with direct and prolonged exposure.
- Needs occasional cleaning to maintain effectiveness since dust renders UV bulbs ineffective.
- Still needs an air filter since UV light doesn’t remove harmful particles from the air.
- UV light is not effective against viruses.
- Needs routine replacement of UV bulbs since they have a shorter lifespan compared to normal bulbs. UV light bulbs cost $120-$250 while the whole system can cost $300 to $600. They’re available in 20, 30 and 40 watt configurations hence won’t cost significantly more than your normal light bulbs.
- Doesn’t work on germs not directly hit by the UV light. Those in the shadows won’t be affected by the light.
- Ozone, which is harmful to your health, can be produced by the UV light.
UV light in HVAC effectiveness depends on how slowly the air passes under the light. The slower it passes, the more effective the light becomes at killing germs from the air.
Precautions when handling UV light
Given the risk associated with using UV light, you should take the following precautions to stay safe:
- Use ‘ozone free’ lamps in your home or business.
- Add interlocks to the access panels so that power to the UV lamp is cut off when you remove the access panels.
- Put in place warning signs and labels for other people in the building.
- Have clearly labeled on/off switches for the lamps.
- Install spy holes where you can check whether the lamp is on or not from outside.
- Safely dispose of the UV lamps at the end of their life.
- Educate others in the building of the dangers of UV lamps.
- Put in place standard operating procedures explain the hazards, control measures, and what to do in the case of a problem.
- Turn off UV lights when cleaning or swapping them with new ones.
- Allow only specific people to operate the lights.
- Use protective gear such as face shields, googles, gloves and closely-knit cloths.
For complex tasks involving UV lights, always let the experts handle them. You can swap and clean a UV bulb but anything beyond that simply puts you at risk unless you have prior experience with UV light.
Do I need a UV light for my air conditioner?
UV lights in HVAC work but you don’t need them unless a member of the household is highly vulnerable to allergens and other dangerous particles. If you already have a properly working HVAC system and your immunity is okay, you don’t need UV lights for your air conditioner.
UV light increases the air quality of the home significantly. It’s also affordable for most people and the choice entirely depends on your needs. While using it, always be cautious to avoid HVAC UV light damage for your skin, eyes and even the objects in the house.