UV Lights for HVAC Systems? Are They Worth the Money? (Updated on Feb 8, 2024)

Note: For those of you who want to install the UV lights by yourself, we filtered most lights in stock this week and publish a post: Best HVAC UV Lights For DIY (Updated on Feb 8, 2023). We will update this list every week as some products could be out of stock due to a notable boost in sales recently.

The thought of mold and bacteria multiplying in the HVAC system and being circulated through ductwork is troubling to anyone who wants a sanitary home. It can be a serious threat to those with breathing issues such as asthma and C.O.P.D.

You’ve heard that ultraviolet lights effectively sanitize air and equipment. Is this true? How much do they cost? Are they worth it?

These are the questions answered in this guide to UV light cost and effectiveness.

Do UV Lights Kill Mold, Bacteria and Viruses?

Ultraviolet lights were shown to kill mold, viruses and bacteria more than 100 years ago. In fact, in 1903, Niels Finsen was given the Noble Prize in Medicine for using UV to effectively treat patients with skin infections.

Today, UV lights are used for germicidal use in hospitals, restaurants and grocery stores. And they have been shown effective in killing sterilizing an HVAC system. Here are two examples:

1). In 2012, a study at Duke University Medical Center showed that UV lights killed 97% of bacteria that were resistant to antibiotics, the so-called superbug bacteria that are the toughest to kill.

2). The Journal of Applied and Environmental Biology reported in 2001 that germicidal UV radiation significantly reduces airborne fungi in air handling units.

Will it Work on the Coronavirus?

This is a question we’re hearing often, and there might be good new! UV germicidal lights are known to kill viruses of many kinds.

Can UV Light Kill COVID-19?

UV light might kill coronavirus! According to the US Centers for Disease Control and Prevention, “Vaporous hydrogen peroxide, ultraviolet germicidal irradiation, and moist heat are the most promising decontamination methods” for COVID-19 commonly called coronavirus.

More on UV Light from the CDC

Testing is still in the early stages, but promising results are expected. In discussing disposable masks, technically called filtering facepiece respirators, or FFRs, the CDC discusses decontaminating them and advises that “Because ultraviolet germicidal irradiation (UVGI) vaporous hydrogen peroxide (VHP), and moist heat showed the most promise as potential methods to decontaminate FFRs, researchers, decontamination companies, healthcare systems, or individual hospitals should focus current efforts on these technologies.”

This video shows an interview with the CEO of Xenex, a manufacturer of UVGI lights. It discusses how it is being used in hospitals for sanitizing and disinfecting purposes.

What Kind of UV Light is Used in HVAC Systems?

The UV lights installed in HVAC systems are Ultraviolet germicidal irradiation lights, the kind being used to kill COVID-19 in tests being conducted.

The CDC warns that lights are more or less effective based on their UV intensity and the amount of time the contaminated surface is exposed to the light.

Since HVAC UV germicidal irradiation lights are on full-time in most cases, the dose is considered quite high.

Promising but not Proven

Tests are ongoing. While it appears that UV lights kill coronavirus, remember that intensity and dose are different for each light.

We recommend that you don’t take your health safety for granted. If you are concerned about potential contamination in your home, clean affected surfaces thoroughly. You might also want to open windows for fresh air unless you believe there is a threat immediately outside your window, which would be rare.

And consider having a UV germicidal light added to your system. If you already have one, make sure the bulb is working.

Fresh-Aire is a leading manufacturer of whole-house UV germicidal lights and other technologies. It claims that, “Fresh-Aire UV systems are tested and validated against bacteria, viruses, mold & fungus…and achieve up to a 99.999% reduction on microorganisms.”

Here is the latest update from Fresh-Aire.

Bookmark this PickHVAC page because we will continue to update this section as relevant testing data becomes available.

UV Light Options for your HVAC System

Two types of UV lights are made for sanitizing your heating and air conditioning system. They have various names including purifying lights, germicidal lights, sanitizing lights and sterilization lights.

Coil Sanitizing Lights:

If you have central air conditioning, then you have an indoor coil. It is a prime location for the development of mold and bacteria. Why?

Because the coil is used to condense moisture from the air to dehumidify your home during AC cycles. As air passes over the coil, dirt, pet dander and other debris stick to its wet surface. The combination creates an ideal setting for the growth of mold and bacteria that can be spread through your home in the passing air.

Coil UV lights are the most common HVAC sterilizing lights. Single-lamp and dual-lamp models are produced. Coil sterilization lights are installed where they can shine directly onto the surface of the coil, and they are left on continuously.

Air Sanitizing Lights:

This type of HVAC germicidal lights are installed in the ductwork bringing return air to the system. Their purpose is to kill airborne germs and mold. Stick and U-shaped lamps are used by various manufacturers.

Some air germicidal HVAC lights are coordinated with the blower motor to turn on and off as it does. These must be hardwired with the system, so installation cost is on the high end of the spectrum.

Also Read: Best HVAC UV Air Sanitizing Lights For DIY

How Much do UV Lights Cost?

There are four costs associated with germicidal HVAC lights: Fixture cost, installation cost, replacement lamp cost and energy cost.

The most popular lights for both the coil and the air ducts cost $80 to $125. Most lower-cost units use a single lamp. Those with higher cost use two lamps and, for air sterilizing UV lights, also include an air filter to clean the air of allergens.

Lamp life is 9 to 14 months for most brands, so expect to spend an average of $15-$50 per year for new lamps depending on whether you install a unit with one lamp or two.

DIY Installation is Possible

Many UV lights for HVAC systems include a 110V plug. They aren’t hardwired. Some have a magnetic mounting bracket for quick, simple installation. The process requires accessing the coil cabinet or ductwork, using sheet metal screws to install a light that doesn’t have a magnetic bracket, and plugging it in.

If you have DIY skills that are at least mid-level, then you might be able to save installation cost by doing it yourself. Complete instructions are included with most lights. We don’t recommend hard-wiring a light yourself – only installing those with a power cord plug.

Note: Be sure to seal up ductwork after installation using pro-grade duct tape or mastic. Air leaks allow contamination of the system, hurt efficiency, reduce indoor comfort and can be noisy.

Additional Benefits

Bacteria and fungus cause two additional problems that are eliminated when they are. First, they cause odors including a musty smell that can infiltrate your whole house.

Secondly, the buildup of the organisms might eventually clog the drain inside your HVAC air handler or furnace. When this happens, AC condensate will eventually leak. This increases the potential for mold and mildew growth and might also cause water damage.

What Else Should Be Done to Prevent Problems?    

UV lights are part of the solution to keeping your HVAC system and ducts clean and healthy. There are three additional steps you can take.

Keep filters clean or fresh: If your filter is washable, wash it per manufacturer’s instructions. If it is a replacement filter, change it every month if you have pets, you smoke or you live in a dusty environment. Otherwise, it can be changed every six weeks to three months depending on how heavily your HVAC system works. Remember, the filter needs attention during AC seasons too, not just when heating.

Use a high-MERV filter: These filters remove smaller particles from the air, so less debris gets into your HVAC system where it can promote bacteria and fungus growth. If you have an older or cheap furnace, it might not be suitable for a high-MERV filter. Check with your HVAC technician or the furnace owner’s manual.

Seal ductwork properly: Gaps in ducts allow dirt, debris, allergens and other impurities to be pulled into the system. Duct sealing eliminates that. Plus, it prevents wasted heat and AC, so can reduce your HVAC costs by 20% to 30% according to Energy Star.

Are UV Lights for HVAC Worth the Cost?

After the cost of the light or lights you choose, you can expect to spend $45 to $70 per year to pay for the energy they use and for replacement lamps. Is it worth it?

Your health provides the answer. If you and household members do not have breathing issues or allergies and if you’re not experiencing higher-than-normal rates of colds and other viruses, then you probably don’t need germicidal UV lights in your HVAC system.

However, some might be reading this post because those problems are a reality in your home. For you, HVAC UV lights can be part of the solution. We recommend these steps:

1). Have your furnace or air handler and coil thoroughly cleaned (though we don’t recommend duct cleaning)

2). Seal ducts to prevent infiltration of contaminants

3). Ask your technician if a high-MERV filter is right for your furnace or air handler, and install one if so

4). Have a UV coil light installed, since the coil is the primary location for the growth of fungi and bacteria

5). If your issues are severe, have a UV air sanitizing light installed in the duct

6). Remember to clean or replace your filter as recommended

If you’d like to discuss having your HVAC system cleaned or UV germicidal lights installed, you can get free local estimates here in 3 minutes. You’ll get your questions answered, and if you want estimates for having the work done, they will be provided. There is no cost or obligation to you for using the free service.

Written by Rene Langer

Rene has worked 10 years in the HVAC field and now is the Senior Comfort Specialist for PICKHVAC. He holds an HVAC associate degree and EPA & R-410A Certifications.