The UV lamps used in HVAC systems have the design of fluorescent lamps. They are installed inside the HVAC system where they inactivate microbes in the air. UV lights have some similarities with fluorescent lamps as both use the same electrochemical processes. UV lights operate when an electric discharge goes through argon or xenon gas and strikes the mercury in the tube to emit UV light. The UV light emitted has a wavelength of about 250 nanometers, according to the EPA.
How Do UV Lamps Purify Air?
Once the lamps generate UV light, they emit it into the surroundings, and it kills microbes. These lamps sport a unique transparent glass envelope that allows the UV-C to transmit unfiltered. This is unlike fluorescent lamps, which use regular glass coated with phosphorus.
A UV lamp uses about 90% of the energy that it receives to generate UV-C wavelength light. About 4% of the energy is released as heat while the rest comes off as visible light. Most lamps, however, will not produce any form of visible light. If there is light emitted, it is a medium blue light from the argon inside the tube.
The mercury UV-C lamps that are common in most households are more effective than other forms of UV-C lamps. They will serve you for about 9,000 hours if you run them continuously as the manufacturers recommend. This means that you need to re-lamp your home every year to make the UV-C lamps effective.
While there are systems that work the same as ordinary UV lamps, there are others that are installed in your HVAC system. All the lamps produce UV-C, which inactivates bacteria, viruses, and other microorganisms. The units pull air into the UV chamber. This air has impurities such as bacteria and viruses in it. When the DNA molecule of the microorganisms absorbs the UV light, the light destroys it. Because these organisms only have a single cell, inactivating the DNA kills them.
Why Is UV-C Effective in Killing Microorganisms?
UV-C is short-wave light. It is one of the three categories of UV light.
UV light exists as UV-A, UV-B, and UV-C. UV-A is the most abundant ultraviolet light from the sun. This light doesn’t cause sunburn and has a wavelength of between 315 and 400 nanometers.
UV-B is less abundant. It is the spectrum responsible for sunburns. Most of the light is blocked, and only 5% gets to the surface of Earth. The light’s wavelength ranges from 280 to 315 nanometers.
UV-C is the most potent of the three spectrums. It has a wavelength of between 100 and 280 nanometers. This means that the photons of light vibrate closer to each other, and the light has more energy. The light is used in UV-C lamps and other devices that disinfect surfaces at home, in hospitals, and in food processing facilities, among other places.
The Types of UV Lamps
UV lamps are single-ended or double-ended. Single-ended lamps have the start and end pins in the same lamp base. These units are great as you can install them in a duct or plenum. They work best when installed downstream of the air conditioning system.
Because the UV lamp doesn’t trap particulates, installing it downstream of the AC makes it more effective in purifying the air. The HEPA filtration system traps particulates while the UV light kills the microorganisms. When you install the lamp into the airflow stream in your duct, it allows 360-degree irradiation, making the lamp more effective. At HB Home Service Team, we can help you pick the right place to install the UV lamp for optimal effectiveness.
Double-ended lamps feature two pins on their two ends. They are available in many varieties, and you can only install them in fixtures of specific lengths. These fixtures need to have the ballast like is common in fluorescent fixtures.
Both single-ended and double-ended lamps come in either high output or standard output. The difference between high and standard output lamps is in their wattage and size of the ballast. You can go for high output lamps if you are looking for the more affordable lamps on a per-lamp-watt basis.
Besides the types of lamps above, you can pick encapsulated lamps. These lamps feature a transparent coating on top of the glass envelope. This coating ensures that the lamp is safe even when the glass envelope breaks. If the lamp breaks, the mercury remains within the protective shell of the lamp.
How Safe Are UV Lamps?
UV lamps are safe for residential and commercial use. The use of fluorescent lamps started in the 1930s. When the use of fluorescent lamps became popular, the FDA set the specs for protecting the lamps from breakage. According to the FDA, the lamps needed to have a shield and a coat or any other mechanism that makes them shatter-resistant. This was for all applications in the food processing industries.
The use of strong materials in fluorescent lamps has continued, and a similar set of standards has been applied to the manufacture of UV lamps. Better, the UV lamps have enough mode advanced coatings that keep the mercury and other components locked in.
The ASHRAE recommends that you switch off the HVACR system for about 15 minutes if the lamp breaks. However, it is unlikely that the lamp will break as the coating is strong. The main concern with these lamps is that they will lead to the formation of ozone in a home.
Ozone (O3) is created when the free oxygen molecules (O2) in the air combine with an oxygen atom (O). According to EPA, ozone makes it challenging for one to breathe and can cause inflammation of the airways. However, that only occurs when ozone is in high volume. Because UV lamps have a protective coating, they will not lead to the creation of ozone.
Today, the FDA recommends the use of UV light to inactivate coronavirus. Although they have only tested the effectiveness of the system in damaging the first strain of the virus from 2019, the light has been able to reduce the prevalence of the virus in indoor spaces. This shows the effectiveness and safety of UV lights.
What Are the Benefits of UV Lights in Air Purification?
The main benefit of these lights is that they have undergone several effectiveness and safety tests from recognized bodies such as the FDA. The lamps do not replace your HEPA filtration system, but rather, they kill microorganisms that the HEPA filter may not be able to trap. UV lamps inactivate bacteria, viruses, and mold spores. This way, you are safe from many airborne diseases that may infect your home.
Install a UV Lamp Today
The HB Home Service Team can help you install UV lamps at home or in your business. We are a heating, cooling, and plumbing company offering installation, repair, and maintenance of HVAC and plumbing systems in Baltimore, Maryland. Call our customer care team today and schedule an appointment.