While HVAC systems keep our living spaces well ventilated at moderate temperature and humidity, they do not have the capacity to trap biological contaminants in the air. However, when UV lights are installed in the HVAC system, they can improve indoor air quality immensely.
Ultraviolet Light Basics
Ultraviolet light is electromagnetic radiation that exists between visible light and X-rays. It features a wavelength range of 100 to 400 nanometers and is of three types; UV-A, UV-B, and UV-C.
UV-C light, which has a wavelength of 100 to 290 nanometers, is responsible for the killing of microorganisms found in the air and surfaces. It does this by interfering with the nucleic acids of organisms such as:
- Aspergillus flavus (common mold)
- Infectious hepatitis
- Influenza (flu)
- Mycobacterium tuberculosis
- Penicillum chrysogenum (common mold)
- Salmonella enteritidis
- Staphyloccocus aureus (MRSA infections)
- Streptococcal pharyngitis (strep throat)
- Rhinoviruses (common colds)
How UV Lights Work in HVAC Systems
When microorganisms are exposed to UV light, their cellular structure is damaged completely as the light breaks down its molecular bonds as well as DNA. Once this happens, microorganisms are unable to reproduce and are rendered inactive in the human body.
UV lights installed in the HVAC system provide an extra layer of protection to the indoor air quality. Air that enters the system is exposed to UV light, which eliminates microorganisms before they are released into your living space.
Although UV lights are typically installed inside the duct network, most HVAC systems are installed into the coil system. By doing so, the coils remain free from mold, fungi, and other pollutants that may undermine the performance of the HVAC unit. For UV light to work effectively, it should make direct contact with the microorganisms to enhance the kill rate. If only partial exposure is provided, users may experience unsatisfactory results.
UV Lights for Air Purification
For households with occupants with serious allergies or asthma attacks, UV lights can come in handy. While the HVAC system alone prevents stuffiness, fitting UV light in these systems could help purify the air. Some UV lighting systems provide more than just coil bathing by using carbon cells to eliminate harmful odors, chemical vapors, and VOCs that may trigger allergies and asthma attacks.
UV Lights to Prevent Microbial Growth
Air conditioning systems have two coils, one inside and another outside. The indoor coil, which is located above the furnace, is usually affected by the water that condenses over it. The darkness inside the unit, together with the wetness of the coil, provides a hospitable environment for microbial growth.
When these contaminants start growing, they can be blown into your indoor air, which could increase respiratory issues. If UV lights are installed, they bathe the coil constantly with the UV-C light, thus eliminating these microorganisms.
Benefits of UV Light Disinfection
UV lamps have been in use since the 1930s to disinfect areas where cleanliness is required at all times. Applications of HVAC UVGI lights are seen in hospitals and medical facilities, food processing facilities, and high-tech manufacturing facilities that require sterile and pathogen-free environments.
UV lamp installation can increase the life span of your system and reduces:
- Lung-related diseases such as asthma, bronchitis, and tuberculosis
- Spreading of airborne diseases
- Use of harsh cleaning agents
- Microbial growth inside the air handler and condensate drain pans
- Growth of mold and fungi inside the HVAC unit
- Foul odors inside your home
- HVAC maintenance and repair costs
- Energy costs as HVAC units work optimally
Types of UV Lights for Air Systems
There are two main types of UV lights for HVAC systems; air sterilization and coil sterilization.
Air sterilization is a complete UV light unit that is installed to sterilize moving air. The UV light is usually installed in the air duct as well as cycles on the air handler blower.
Coil sterilization is a stick-type light that is typically installed in the HVAC’s return air duct. It runs for 24 hours a day. It is the most popular HVAC UV light and is also the most budget-friendly.
UV Light Installation
For UV lights to be effective, their placement is of high importance. These air purifiers must be mounted next to the evaporator coil as well as downstream from the coil. UV rays must bathe both the cooling coil and the water drain pan, which is located beneath the coil.
If these mounting requirements are not heeded, algae, bacteria, mold, and slime will grow on the blower, cooling coil, drain pan, and ductwork. When this happens, your indoor air quality will be compromised.
How to Choose UV Lights
There are lots of UV light indoor air quality products in the market, so deciding on one can be rather daunting. To help you figure out which one to go for, consider the following:
- High light intensity – always go for a UV lamp that outputs UV-C lights and at a higher intensity as it works more effectively. UV-C light is efficient in killing disease-causing microbes.
- Ease of installation – when selecting a UV lamp, select one with an easy and straightforward installation process. Some lamps require drilling holes for the screw, while others have aluminum tape screws or magnetic brackets. Depending on what labor you are ready to put in, select accordingly.
- Power consumption – UV lamps have different power consumption abilities due to the technologies employed to ensure they are energy efficient and the bulb sizes. If you are looking to save on energy costs, you should choose a UV sanitizer whose bulb has a titanium dioxide reflector and has lower wattage.
- Extra features – although all UV lamps work to eliminate airborne allergens, lamps that offer extra features stand out from the rest. Some UV sanitizers have a bulb viewing area as well as a warning light indicator, which notifies you when a bulb has burnt out and needs replacement.
How Much Do UV Lights Cost?
UV lights tend to be costly as they are gaining popularity in residential homes. The cost depends on the available models in your locality and your air quality needs.
You can get a good HVAC UV light for under $100. However, there are installation costs that you need to factor in, which could cost somewhere between $450 and $700.
Depending on the model you pick, you will also be required to replace the UV bulbs every 12 to 24 months. Replacement bulbs could cost about $70.
The Disadvantage of UV Lamps
While UV lamps improve our indoor air quality, they have some disadvantages as well. Some UV lamps, for instance, break down oxygen into ozone, which is harmful to occupants with respiratory issues. To avoid this issue, select a UV lamp with bulbs that combine quartz and titanium. These bulbs prevent ozone generation.
Another downside of these UV lights is that they have no action against some allergens and dust. Therefore, you cannot pin all your hopes on these air purifiers as some allergens can still float freely in your living space.
Call in the Professionals
If you are still at crossroads on which UV lamp to install in your HVAC system, we, at Holbrook Heating & Air Conditioning, are at your service. We offer our clients exceptional services in AC installation, replacement, AC repair and service, maintenance, and tune-ups, and heating in upstate NY and the surrounding areas. Request a service today!