UV air purifier systems, also known as UV germicidal irradiation (UVGI), make use of UV light, specifically the short wave form known as UV-C, to kill airborne microbes including bacteria, viruses, and mold. This helps to improve indoor air quality by eradicating airborne pollutants.

Sometimes, these systems can be reinforced with HEPA filters which further help to protect against dust and other airborne microorganisms, particles, and allergens.

But how exactly do these systems work?

How Do UV Air Purifier Systems Sanitize The Air?

UV air purifiers come with features known as UV lamps, and these serve as the main component of UV air purifier systems. Their function in UV air purifier systems is to emit UV-C light which functions as the primary disinfectant in the unit.

Now, UV-C light may or may not be visible to the naked eye. However, its visibility would depend on the kind of material the emitter is made of. When visible, UVC-light shines with a slight bluish hue.

Much better than visible light, UV-C rays are powerful enough to destroy the DNA of microorganisms that they get in contact with. And as bacteria are typically unicellular, the destruction of their DNA is enough to lead to their self-destruction which, in turn, renders them harmless.

Following is how UV air purifiers sanitize the air...

When air gets sucked into the air purifier system, it first passes through the HEPA filter. After this, the air then goes into a small chamber which is where it comes in contact with the UV-C light.

From there, the air could either be released into the room directly or might pass through yet another filter before it gets released. It all depends on the model you have.

Before you get scared, the UVC-light used in UV air purifier systems are never released into the room which the system serves. Hence, you will neither see the rays nor be exposed to them.

Now, keep in mind that UV lights degrade with time. On average, a UV light bulb should give you between 5,000 to 10,000 hours of service. This means that you'd have to replace your UV lamp annually to keep your UV purifier performing optimally.

Factors that affect the durability of UV lamps include the design of the lamp, surrounding temperature, as well as humidity. These, ultimately, also affect the overall performance of your UV air purifier system.

UV Air Purifiers For HVAC Systems

UV air purifiers for HVAC systems are of two types. There are UV object cleaners and in-duct air purifier systems.

UV Object Cleaners

The coil of an air conditioning unit is a convenient and conducive breeding ground for all kinds of pathogens -- visible and invisible.

Consequently, UV object cleaners are typically placed beside this coil to help destroy these organisms through the emission of UV light. This way, harmful organisms do not get sucked into your ventilation system which could negatively impact on your health and that of others in your home.

In-Duct Air Purifier Systems

UV in-duct air purifiers, on the other hand, are a pricier but more comprehensive option. Installation involves your technician fitting UV lamps into the ductwork of your HVAC. Think of it as placing the sun in your ductwork.

Now, as the air circulates through your HVAC, it comes in contact with the UV lamps in the ductwork. These UV lamps would then emit vaporized hydrogen which will destroy airborne microorganisms, spores, mold, fungi, and even odors contained in the air. The now treated air would then be released into the room.

UV air purifier systems for HVAC are quite pricey, with in-duct purifiers being the pricier option. However, they do not take long to install and you're usually charged a flat rate for installation including parts and labor.

Do UV Air Purifier Systems Really Work?

There are various scientific studies that have proven that, at a specific wavelength and duration, UVC-light can be very effective at killing off harmful microorganisms. And not only microorganisms, UV-C light has also been proven to be effective at taking care of airborne allergens as well.

Still, it is important to state here that UV air purifier systems are not equal. Many of these units are carried by brands who make exaggerated claims that cannot be backed by hard data. Hence, you must be watchful.

Now, there are four major factors that determine the effectiveness of any UV air purifier system:

1. The exposure time of the pathogen to the UV-C light. Generally, even half a second is enough to cause damage serious enough to render bacteria inactive.
2. The intensity of the UV-C light as well as its wavelength. Optimal wavelength of UV-C light to kill off pathogens is 254 nanometers.
3. The proximity of the pathogens to the UV-C light also affects the effectiveness of the purifier system. Naturally, the closer, the better.
4. Finally, there's the "air changes per hour (ACH)" factor. If your purifier can exchange the air in the room very frequently, obviously, the air in the room would be fresher.

Will UV-C Light Kill The Coronavirus?

The United States Center for Disease Control and Prevention says that ultraviolet germicidal irradiation is a promising decontamination method for the COVID-19 virus. Though tests are still in their early stages, the results look promising.

UV Air Purifier Dangers

Many ask "are UV air purifiers safe?" and the answer to that question isn't exactly straightforward. Some systems are safe and others are not. Bear in mind that the UV air purification technology is still quite recent, hence, this nuance is to be expected.

The main danger with UV air purifier systems is ozone production. Although ozone is present in the atmosphere, it can have negative health complications on living organisms if they are exposed to it in high enough concentrations. In smaller concentrations, however, ozone is safe.

To mitigate this danger, therefore, many manufacturers now overlay their UV lamps with a substance that keeps the lamp from producing excess ozone. But even better, some manufacturers avoid UV lights within the wavelengths known to produce ozone altogether for the safety of their customers.

Are UV Air Purifiers Worth The Money?

Homes where allergies, breathing issues, and colds occur frequently would seriously benefit from UV air purifiers. In contrast, if these issues are not a real threat to you and yours, then installing them might not be absolutely necessary.