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It has been over a 100 years since the discovery that ultraviolet light kills germs. This discovery has led to the use of ultraviolet lights for all kinds of uses: sterilizing hospitals, sterilizing water, germicidal lamps in food establishments, and even curing nail polish faster.
It was only natural then that a bright inventor would figure out that UV light can be applied to improving indoor air quality for residential HVAC systems. Let’s go over the technology of UV lights for indoor air quality and the types of UV lights available for residential HVAC systems.
Quick Comparison Chart for the Best UV Lights
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Can UV Lights Really Help My Air Quality?
The UV light can help eliminate many types of fungi, bacteria, germs, viruses and pathogens. Usually, the UV lights are installed within the air handler, which remains turned on 24/7. The HVAC UV lights are effective at controlling mold inside the air handler, as all mold in line-of-sight of the UV bulb will be killed, keeping the coil mold-free.
Several factors will affect the effectiveness of the UV lights installed in your AC system, such as the intensity, number, placement and direction of UV lamps. The surrounding temperature and humidity levels of your home and the reflectivity of surrounding surfaces will also have an impact.
Two studies point to the effectiveness of UV light in killing mold and bacteria, one in hospitals and the other in a commercial HVAC system. In 2012, researchers at Duke University Medical Center used ultraviolet radiation (UV-C) to nearly eliminate drug-resistant bacteria in 50 hospital rooms, reducing the number of bacteria by more than 97%. In 1996, an NCBI study installed UV lights on certain floors (and not on others) of an office building for four months to measure and compare the fungal levels of each floor. It found that “the fungal levels following UV operation were significantly lower than the levels in control AHUs (air handler units).”
How Do UV Lights Help?
Fungal contamination in HVAC units is a widespread issue that shouldn’t be ignored as it often contributes to building-related diseases, like infectious diseases, allergic rhinitis, asthma and hypersensitivity pneumonitis, according to the National Center for Biotechnology Information.
Ultraviolet light helps kill a variety of harmful bacteria and mold, but most UV lights have no action on some other allergens or dust. UV systems should prevent the organic build up on the surfaces of your HVAC system’s coils, and in your ducts. An additional benefit of UV lights is that they improve airflow and the energy efficiency of your HVAC system, as well as eliminating the need for regular duct cleaning.
Ultraviolet (UV) lights for air purification are more important for folks who reside in humid areas prone to mold growth or for those with severe health issues. You might argue that filters are sufficient for you, but the best HVAC UV lights do a better job at disinfecting and sterilizing the air in your home.
Types of UV Lights for Your Air System
There are two types of UV lights for HVAC systems, Coil Sterilization and Air Sterilization.
In Coil Sterilization, a “stick type” light is installed inside the return air duct and sterilizes the air handler coil. A coil sterilization UV light runs 24/7 and is the most common type of HVAC UV light. It is also the most reasonably priced.
In Air Sterilization, a complete UV light unit is installed that sterilizes moving air. The UV light unit is installed in the return air duct and cycles on with the air handler blower.
Installation, Longevity and Cost
Placement of the lighting system is important for high effectiveness. The UVC purification lights must be mounted next to the evaporator (cooling) coil and on the downstream (cold air side) of the coil. The UV rays must shine both on the air conditioner cooling coil and on the water drain pan underneath the coil (if installed) because this is the main area where mold spores grow.
If the UV lamps are mounted elsewhere, then slime, algae, bacteria, and mold can grow on the cooling coil, drain pan, and even the blower and ductwork. As a consequence, these organisms will contaminate the air that you're breathing, throughout your living space.
The negatives of a UV filtration system are that it can sometimes be costly as it is a newer form of air purification. Depending on your area and the available models nearby, you should be able to find a system that meets your budget while still maintaining air quality needs.
Functionally, UV systems are designed to work with a particle filter rather than as a stand-alone item, so regular filter replacement or cleaning is still required.
In addition, the UV bulbs will need to be replaced every 12 to 24 months, depending on the model. One UV stick light bulb is estimated to last 9000 hours, just over 1 year. Replacement bulbs cost about $70 and replacing the bulb during each annual HVAC service and maintenance is nearly effortless.
For just under $100 per year including electricity and tube replacements, you can have your UV lights purifying the air.
Review of the Best UV Lights for Air Purification
UV lights for HVAC come in various shapes and sizes, and with different power ratings. Although some may offer more features than others, you should look for UV lights that output UV-C light and have higher light intensity for maximum effectiveness. Be sure to check your system in order to choose the right type of bulb; they are not necessarily “one size fits all.”
Bio-Shield UV-C Air Sanitizer System
This is a UV air sanitizer that once installed, works on more than just your usual microbes (mold, mildew and bacteria). It works on other airborne irritants such as dust mites and pet hair, which can cause breathing problems such as asthma.
It also improves the efficiency of your AC unit by continuously cleaning the coils and the drain pan. The result is improved air conditioning heat transfer, and an increase in the net cooling capacity as well. Coupled with the efficient 25 watt bulb, the outcome is an upsurge in the unit’s energy efficiency, and lower power bills.
Installing the UV light sanitizer is pretty straightforward and is done in four easy steps. First, you locate the galvanized duct within the AC unit’s installation and attach the mounting template to it. Then drill holes in the duct using the 2 and 7/8 inch bit that comes included at purchase. You then mount the unit using the three screws that come with the product. Finally, insert the bulb and plug the sanitizer to a power source. It should emit a continuous blue light to let you know it’s working fine.
The Bio-Shield UV-C Air Sanitizer System eliminates the need to pay for duct cleaning by stopping the build-up at source. Most of the cleaning done on ducts is to remove the dirt, gunk, and mold build up in the AC.
This light prevents organic material from depositing on the cooling coils, drain pan, and other surfaces inside the AC unit. There have been some customer complaints about the efficacy of the sanitizer in areas of high humidity. In some instances, mold accumulates at the base of the light.
When it comes to UV sanitization systems, the Bio-Shield UV-C Air Sanitizer System has the best combination of features and ease of use for its price point. This is definitely something worth investing in.
OdorStop UV Air Treatment System (OS72)
This a professional grade air treatment system that works with most standard AC units. It uses two 16 inch bubs that put out 32 watts each. The lights have an LED indicator to make it easier to monitor whether they’re working as they should. If you need to, you can find 12-inch replacement bulbs. These are ideal for homes with installation ducts that are shallower than the standard.
The OdorStop UV Air Treatment System eliminates odor-causing bacteria, mold, mildew, viruses, as well as pet dandruff and other allergens. This makes it a good investment for homes that have children or the elderly to take care of.
The body is made of high quality aluminum, which makes this a durable and hard to break product. The installation process is also easy, and the package comes with picture directions. You get a cut-out template to help with the drilling, mounting screws, and foam tape, together with the UV sanitizer.
Simply use the template to drill holes into the duct, mount the unit onto the AC, and plug it in. It’s important to note the power cord is only 6 feet long, which some customers feel is too short. To help with the installation, there’s a detailed step-by-step video from the manufacturer. You can watch it here.
There have been complaints about the integrity of the bulb support, and its long-term effects on how the sanitizer works. It’s wobbly, and after 6 to 8 months of use, it becomes weak and allows the bulbs to sit lower, thereby limiting their efficiency. Bulbs also tend to fall off or burn out quickly when this happens, and you may end up replacing one every few months.
This is a very good sanitizer with an excellent record. It’s easy to install and easier to use. The problem with the bulb support is something they should work on though.
If you’re looking for a UV light air sanitizer that has very little fuss on installation, this is it. The process is one of the easiest among the sanitizers on this list. Since it can be installed above or underneath the evaporator, you only need to find a place to stick the magnetic bracket onto inside the air handler.
It uses a standard 120V power supply, and doesn’t need any special electrical plugs to work. The main source of light is a 14 inch UV light bulb with germicidal properties. This works on mold, bacteria, and allergens. It’s also designed to work as a cleaner. It prevents the growth of organic material on the surface of the AC coils, or in the drain pan, where accumulated dirt can form a smelly goo. The bulbs only need to be replaced once a year, and replacements are readily available.
By continuously cleaning the coils, this lamp improves the energy efficiency of your AC unit. The magnetic bracket is built to last as long as the product itself, so you don’t have to worry about it coming loose and the lamp falling off. The installation and placement is designed to ensure the light isn’t affected by any condensation and moisture in the AC. Moisture simply drips into the drain pan, away from the UV bulb.
It has a 6 foot lamp cord, with 5 feet from the ballast to the transformer. It’s also pretty light, weighing only 1.8 pounds. There’s a limited one year warranty on the product. That’s on the lower side, since most sanitizers come with a minimum 2 year warranty. This UV purifier is ozone free.
The biggest selling point is its ease in installation, and it works well as an air sanitizer. The yearly bulb replacement is also nice, since some other sanitizers in the market take about 6 months before needing a bulb replacement.
Air Purifier UV Light for AC
Longevity counts when it comes to UV sanitizer bulb. And with its 13,000 hour lifespan, you’ll go over a year-and-a-half before you have to worry about a replacement. This reduces the costs of routine maintenance considerably. The light comes from twin bulbs for a combined 0.36 amps. This means the total output is less than 25 watts, which is pretty energy efficient. These bulbs are readily available when a replacement is required.
It’s important to make sure the bulbs are not touching anything while the unit is in operation – this will result in bulb damage and burnout. The installation process is a straightforward 15-minute exercise that makes for a fun afternoon DIY project. You use a template to outline and drill two holes – measuring about an inch in diameter – into your AC duct. After that, you simply slip the lamp inside the holes.
Mount it using the self-taping screws provided, and attach the aluminum strips that come included in the box. The final step is to plug in the lamp to a power source. The cord is a good 9 feet, which gives you enough room. The design is minimalist and compact, to reduce the chances of accidental damage, and keep maintenance at a minimum.
There have been customer concerns about the inefficiency of mounting structure. It means that every year, you’ll have to unscrew the entire unit and replace the bulbs when the lifespan runs out. The build quality has also been called into question, and you may have to be extra careful not to drop the unit. This could result in irreversible damage.
This is a delicate UV light sanitizer that’s designed to work with the least parts possible. It’s also budget friendly. Be careful not to jar or drop it during installation, and that the bulbs are not touching the sides of the AC unit.
This is an efficient UV light sanitizer that works on 99% of both airborne microbial organisms, and other VOCs (Volatile Organic Compounds). This is done through the photocatalytic oxidation process, where a combination of Ultra Violet light from the bulbs and Titanium Oxide are used. The process is extremely thorough, making this an ideal purchase for households with people who suffer from respiratory complications.
The build is a unique design that increases energy efficiency in two ways. The first is by increasing the efficiency of your AC unit, ensuring mold doesn’t accumulate on the coils. It also uses up less power when running, by incorporating a titanium oxide reflector, which amplifies the effects of the sanitizer.
The installation process is easy; you just cut a hole in the duct, insert the lamp with the filter, and then seal the plastic frame with easy to use aluminum tape screws. The power cord to plug it in is a normal 6 footer, and you may have to make arrangements for an extension cord if your outlet is farther. Bulbs for the D200 Dual lamp Air Purifier Whole House sanitizer last about a year before you need to replaced.
These replacements are reasonably priced and readily available. There’s no indicator for a burned out bulb, so you have to keep periodically checking to see if any of the bulbs isn’t working. The bulb replacement process is inconvenient though. You have to physically remove the entire unit and install it afresh every time.
The intelligent purifying process that combines photocatalytic oxidation and energy efficiency is a big selling point. If you intend on using them in a space larger than 3,500 square feet, you can install more than one unit.
This is a 36watt device that’s made entirely from plastic. It comes already pre-assembled and requires a simple install. It’s white in color, which allows it to blend in with your run-of-the-mill AC unit. The bulbs are only 14 inches, and will fit even in most of the shallower models. It mounts easily above the cooling coils in the in your central air conditioning, and it’s designed to run continuously.
The bulb’s shelf life is about a year, and the unit doesn’t require any other maintenance. It kills 99% of the mold inside your AC, which in turn improves the efficiency of the entire unit. It also kills up to 75% of various bacteria that pass through (or near) the AC unit. (It’s effective for 15 to 18 feet.)
The UV light doesn’t produce Ozone and is safe to use indoors, even in homes with people and pets. The main selling point for this UV sanitizer is its collection of nifty features. One of these is the sealed unit design.
This protects the installer and you, the home owner, from accidentally coming into contact with electricity, both during installation and running. It also has an intelligent bulb protection design that prevents the bulbs from coming on if they’re in contact with anything, or in case of improper installation. There’s a special light pipe that allows you to safely look at your bulb. You have the option of getting an AIRWATCH indicator with purchase. It lets you know when a bulb in the unit needs to be changed.
Most times, it’s the small things that matter to the customer. The safe seal design, the bulb protection feature, and the viewing pipe are a big plus in all round convenience.
How to Choose UV Lights
There are a lot of UV light sanitizers in the market, which could make it a problem when deciding which one to go with. Here are a few things to look out for, which could help narrow it down:
The installation process should be as easy and straightforward as possible. It should also include the least amount of manual labor. Some UV light sanitizers require that you drill holes for screws, while others come with aluminum tape screws. There’s even an option for a magnetic bracket. This would be important for those who lead busy lives and don’t have the time to install the sanitizer or wait for an electrician to do it.
UV sanitizers consume different amounts of power, which changes depending on the manufacturer. This is because every manufacturer uses different technologies to make them energy efficient, including the addition of a titanium oxide reflector. The wattage of the bulb also comes into play here. Some sanitizers use 9 watt bulbs while others use larger 18 watt bulbs.
Most of the UV sanitizers will work on mold and other airborne allergens. The swing vote might come from extra features. Some of these include a bulb viewing area, and a warning light indicator. It goes on to warn you when a bulb has burnt out. The bulb replacement process should also be as easy as possible.
How to Install a UV Light in HVAC
A lot of people tend to be intimidated by the process of installing a UV light in HVAC. But the truth is that it is very easy and can be easily achieved without professional help. Let’s take you through the step by step guide on how to do it so you can understand it better.
The first thing to do is to figure out the voltage you’re working with, which in this case scenario is 240V. Furthermore, safety is the first thing to consider, thus always shut your power off.
In order to mount the transformer, hook up the orange wire to the high voltage, whereas the white wire is the common.
Take the other two leads (red and black) and wire net them to the side as they may shock otherwise.
Secure the wires in place and torque it down. It’s important to make sure it’s tight as the electricity vibration can cause it to short.
The next step is to mount the power supply; however, make sure that the power supply is in a suitable location inside the control panel of the air handler. When mounting the power supply, make sure you don’t overtighten it as its plastic and may break.
It is very important to establish a separately derived power system for the UV lights. If that is not the case, it causes problems with the condenser coming over the heat pump.
Twist and turn the low voltage wires and make sure they are long enough then hook them to the transformer.
Now that you’ve managed the transformers in the control panels, take the low voltage wire that fits in the UV light. However, when dealing with the UV light, it’s important to not touch the bulb as the moisture and oils in your hand can shorten the life of the bulb.
Furthermore, the UV bulb will be mounted on the bracket as the bulb will fit inside the coil. Take the UV light mount it to the magnet and put it in. Plug it in very carefully.
After you have mounted the UV light behind the coil, it’s important to put the shield back on.
Then, you can go ahead and put the aluminum panel on. And the job is done!
Now, if this description isn’t sufficient for you to understand the process, that’s fine, you can go ahead and check the video below. It will surely help you clear any remaining confusion that you may have.
When looking for the best UV lights for your HVAC system, ensure that they emit UV-C light, which is the most effective at killing germs and preventing fungal buildup. Installation at the right location within the ductwork or air handler will ensure effective performance.
Although UV lights can be helpful for those who live in humid areas or those with severe health issues, they should be used in conjunction with an air filter.
People Also Ask
When it comes to buying the perfect UV light, people are often puzzled as to which route to go. Therefore, we took the liberty of answering your most frequently asked questions in hopes of clearing out any queries you may have left. Have a look:
How Much is a UV Light for HVAC?
You should be able to get a good UV light for HVAC in under $100, but that would depend. However, the real cost is associated with its installation, which can cost from about $450 to $700. The factors affecting it include the type of UV light system chosen, the wavelength of light emitted, etc.
Do I Need a UV Light in my AC Unit?
It can have a big positive impact; thus, it is a good investment. UV light technology is tried and tested to reduce fungal growth inside an AC unit. Therefore, it can reduce the production of airborne pathogens and improve air quality. However, it needs to be installed properly for that to happen.
Where Do You Put UV Light in HVAC?
In order to sterilize the air, you need to put the UV light in the return air duct. It then works with the air handler. Furthermore, the complete UV light system works to sterilize moving air, which is pushed through the HVAC system.
Are HVAC UV Lights Worth it?
Yes, they are worth investing in if you care about air quality. Moreover, it has been proven that a UV bulb kills any mold that is in its sight, and thus, it effectively controls the growth of mold in the coil.
Do HVAC UV Lights Create Ozone?
According to two different studies, UV bulbs that are being used in HVAC systems for the purposes of sterilization and irradiation do not create excessive ozone concentrations.
What Bacteria Does UV Light Kill?
In order to kill bacteria, a certain germicidal light wavelength is required, which is of 185-254 nanometers. A very common example of a pathogen killed by UV light is E. coli. But that isn’t all! High-frequency UV radiation isn’t just effective in killing bacteria but also viruses, molds, and other microorganisms.
How Much Bacteria Does UV Light Kill?
This entirely depends upon the dosage of UV given plus the exposure time of the bacteria or pathogen in general. Dosage is the product of intensity and exposure time, and it is measured in microjoules per square centimeter. The dosage required to kill 90% bacteria and viruses range from 2000 to 8000 microjoules per square centimeter.
Does UV Light Purify Air?
Yes, when a system of air conditioning uses UV lights, it has the ability to kill airborne microorganisms, which in turn improves the air quality. This is precisely why UV light is used as a means of sterilization for hospital equipment.