HVAC UV Light: Everything You Need to Know

We all know that UV light is used in hospitals and other establishments where sanitation is extremely important. But can this light be as effective, if installed in your HVAC system?

UV light has been successfully used within heating and cooling systems – it helps keep the unit and the air in your house safe from various microorganisms. However, the lamps are not cheap and it has been proven that UV light can produce ozone at short wavelengths.

In our guide “HVAC UV Light: Everything You Need to Know”, you will find out, if the lights are worth the investment and whether or not there are some associated risks that you should be aware of.

UV Light In HVAC – Is It Effective?

The UV lights used in HVAC systems are sometimes referred to as ‘UVGI (ultraviolet germicidal irradiation) systems’. These lights are able to target mold spores, bacteria, and viruses.

How does it work?

The systems produce the same type of light that is present in the sunshine but at a higher intensity. Such light is able to destroy the nucleic acids of the microorganisms. 

As a result, the DNA of the bacteria gets damaged, so the microorganisms are not able to reproduce any longer (some die right away).

Do bear in mind that UV light affects only living viruses and bacteria. Dust and pollen, for example, will not be affected by the light at all.

Fact: Ultraviolet light is not known to be effective against not all viruses and bacteria. Rhinoviruses, SARS, Streptococcus variants, and some other microorganisms might be able to survive.

It is important to understand that, in order to work its magic, the UV light has to be installed correctly into your HVAC system. Moreover, the system should have the right:

  • Number of lamps
  • Duct reflectivity
  • Lamp wavelength and intensity (the most common wavelength used is 254 nm)
  • Lamp position

Image source: https://www.achrnews.com/articles/143318-covid-19-reveals-importance-of-uv-c-in-hvac-industry

The effectiveness of your UV light won’t be as high if your ductwork has leaks. The vacuum that is created in the ducts will draw in plenty of contaminants through the holes – this will limit the effect.

Should I Use Air Filters Together with UV Lights?

Yes, you should definitely do that to increase the efficiency of the whole system.

Ideally, you should go for a HEPA air filter that is going to take care of the larger particles, while the UV light is going to eliminate the microorganisms. In fact, it is incredibly important to use these two ‘weapons’ in conjunction as any large particles can shield the bacteria and viruses from the bombardment of UV light.

Do bear in mind that you should first get a good-quality air filter and only then invest in a proper ultraviolet lamp as the latter is an additional air-cleaning measure.

What Types of UV Light Installations Are There?

You can choose between two different types – coil sterilization UV lights and air sterilization UV lights.

 Where is it installed?How does it work?
Air sterilizationHere, the ultraviolet light is able to disinfect the air as it travels through the return ducts. The lamp is coordinated with the blower motor, so it works only when the system is on.This type enhances the duct’s reflectivity within a certain part of the ductwork. As a result, the strength of the UV light is at its maximum and the system becomes incredibly effective.
Coil sterilizationIs installed in hard-to-reach places – some filters, condensation pans, cooling coils… The light shines all the time to prevent the growth of mold.Such a type is installed in order to target sensitive areas that are prone to microbial growth. It helps disinfect the ‘deepest’ parts of the system, including the fins, edges, grooves, and seams. 

The Pros & Cons of UV Light In HVAC

HVAC UV Light – Benefits

  • Do UV lights improve air quality? Yes, if the thing is installed properly, the UV light that has the right wavelength is going to eliminate many types of microorganisms.
  • Ultraviolet lamps help get rid of mold and mildew. Some lights are strategically installed deep inside the HVAC unit (between the filter rack and the cooling coil, for example).Coils tend to get wet because of condensation. Such areas that have moisture are perfect for the development and growth of mold and mildew.However, a UV light will help maintain such ‘vulnerable’ places clean by keeping this stuff from growing.
  • UV lights eliminate odors. Volatile Organic Compounds are a source of odor-causing chemicals. Tobacco, paints, cleaning agents, and other things not only have a strong smell but also attribute to various health problems, starting from headaches and ending with throat irritation.UV lights are able to eliminate VOCs from the ventilation system and the air you breathe.
  • UV lights improve the efficiency of your HVAC. The lamps will organically clean coils and the air that travels through the system. As a result, the unit’s capacity will be restored by up to 35%.A cleaner HVAC system also means lower energy bills, by the way.

HVAC UV Light – Disadvantages

  • If someone in your household suffers from allergies, a UV light will not alleviate the symptoms as it can’t deal with dust and dead fungi.
  • Only certain wavelengths can be used for germicidal control. Unfortunately, not all manufacturers can be trusted.In case the UV light is under 200 nm, it might be producing ozone. If there is an HVAC UV light smell that reminds you of metal or an electric spark, it looks like the system is producing ozone. Tip: UV-C is most effective for germicidal control. This is shortwave light with a wavelength between 280 and 200 nanometers.Hint: For your own peace of mind, you can try finding a lamp with quartz glass doped with titanium. This addition helps make sure that UV light of the wrong wavelength doesn’t get released (the glass is going to absorb the 185 nm UV-C, for example).
  • Direct exposure to UV-C light is hazardous, especially to the skin and eyes. The technician has to be able to install the lamp in such a way so that no UV light ever reaches the eyes of the people living in the house.This is not exactly a disadvantage, but the fear of getting exposed to UV light can make some people change their minds.
  • UV lights are definitely an investment. You would have to splurge on the lamps and the installation.Even though UV lights can help you save on the maintenance of the actual HVAC system, the maintenance of the lamps might cost you a small fortune. Below we are going to discuss the costs associated with UV lights in more detail.
  • If installed incorrectly, UV lights can damage some parts of the HVAC system. The lamps might destroy non-UV-stabilized plastics in the air handler, as well as break down the flex duct and drain pan in as little as 2-3 years, in some cases.So, HVAC UV light damage (photodegradation) is one of the things to keep in mind.

How Much Will It Cost to Install UV Lamps in Your HVAC?

The HVAC UV light installation cost is going to vary and depends on the type of lamp you want to go for. Do bear in mind that you would have to pay for the actual UV light, the lamp, the installation, and the energy that the light is going to need to work.

 Light costInstallation costLamp costEnergy cost
Air sterilization$80-$400$150-$295$15-$125$15-$30
Coil sterilization$60-$285$100-$225$10-$60Usually, coil UV lights are on all the time, so the energy costs might be higher for this type of light.

The main difference between the more expensive options and the cheaper ones is that the latter usually use a single lamp, while the costly ones have two lamps (some even include an air filter in the HVAC UV light kit).

Installing UV lights is definitely not cheap. But, unfortunately, this is not where the expenses are going to end. The maintenance of these lamps is relatively expensive as well.

HVAC UV Light – What Kind of Maintenance Is Required?

  • The lamps have to be kept free of dust as it diminishes the effectiveness of the lights. You should wipe the lamps with a cloth every 6 months or so, but remember to switch the light off and follow the safety rules before getting close to the lamps.
  • When cleaning the UV lights, avoid touching the surface of the actual lamp. Your fingers contain oil that is going to diminish the light’s effectiveness and can cause the device to heat unevenly.
  • A UV light has to be replaced annually. Though it will continue to shine, its effectiveness is going to significantly decrease after around 9.000 hours of use.The coil sterilization lamps can be changed a little less often – about every 2 years.Be prepared to pay for the lamp and, sometimes, the installation (anywhere between $110 and $420).

What Is the Right HVAC UV Light Placement?

It is crucial to place the light in the right part of your HVAC system. Otherwise, the whole device is going to be ineffective (in some cases, it might even become harmful).

Image source: https://nrs.vegas/products/hvac-uv-lights

First thing first, only a specialized professional should take care of the process. A technician will be able to install the UV light inside the evaporating unit, in such a case, the air will always pass through the light as it circulates.

The expert has to wire the light to the unit so that it starts working only once the system is on. Finally, a highly skilled professional would make sure to check the whole HVAC system for any leaks and will also fully clean the air handler system.

How Long Does an AC UV Light Last?

When it comes to HVAC UV light replacement, there are a few important things that you have to bear in mind. 

The lamps have to be replaced on a regular basis, otherwise, they will become completely useless. 

Germicidal UV lamps have an average life of 5.000-9.000 hours. Of course, the light will still continue to shine after the time is up, but, unfortunately, it is not going to be effective in any way.

In general, you should change the lamps every year, but some brands manufacture UV lights with a 6-month lamp life, so make sure to consult the instructions.

Even though coil sterilization lamps are usually working without a break, air sterilization UV lights work ’harder’. So, you might have to replace the latter a bit more often. 

Do HVAC UV light purifiers really work?

UV light has been used in the medical industry for decades already. Throughout the years it has been proven that this light at certain wavelengths is able to destroy a percentage of microorganisms.

What is the major disadvantage of UV light as a disinfectant sterilant? 

For a lot of people, the main con is the price. UV lights, the lamps, and the installation of the device can cost you up to a few thousand dollars. 

Moreover, to ensure that the lamps are able to effectively get rid of the microorganisms, you would have to replace them annually (sometimes, once every two years).

Some people are also afraid of UV light in general. But the great news is that there is nothing to worry about if you have managed to find a highly-skilled professional to install the UV lights.

The lamps have to be placed in a certain part of the HVAC system. This will help make sure that the UV light is effective and safe for all the members of the household.

So, do you need UV light for HVAC?

If you can afford a high-quality UV light, the installation of the lamps is going to bring you quite a few amazing benefits.

The light will improve air quality, eliminate certain odors, and even improve the overall efficiency of your HVAC system. 

To achieve the best possible result, use UV lights with HEPA air filters.