Do HVAC UV Lights Actually Work? (2024)

You know, when homeowners come to me with concerns about mold, bacteria, or pests in their air ducts, they’re often surprised to learn about a nifty little solution called HVAC UV lights. The idea of blasting your ventilation system with ultraviolet radiation might seem like some sci-fi gimmick, but let me tell you, these things really pack a punch.

We’ve been utilizing the power of UV-C for years to keep facilities free from unwanted critters and contaminants. It’s a tried-and-true method that hospitals have relied on for decades to maintain a sterile environment. And now, homeowners can harness that same technology to keep their indoor air clean and fresh.

That said, installing UV coil-sanitizing lights in your HVAC system isn’t a magic wand that’ll instantly purify the air in your home. There are a few factors to consider, like the size of your home and the placement of the lights. But when done right, these bad boys can be a game-changer for anyone looking to breathe easier.

What Are UV Lights?

UV lights, or ultraviolet lights, are a type of electromagnetic radiation with wavelengths shorter than visible light. While visible light has wavelengths between 400-700 nanometers (nm), UV light falls in the range of 100-400 nm.

There are three main types of UV light radiation:

  1. UV-A (315–400 nm): This has the longest wavelength and is not absorbed by the ozone layer. It’s the type of UV radiation in tanning beds.
  2. UV-B (280–315 nm): This has a shorter wavelength and can cause sunburns. The ozone layer absorbs some UV-B radiation.
  3. UV-C (100–280 nm): This has the shortest wavelength and is completely absorbed by the ozone layer and atmosphere. However, it is used in germicidal lamps to kill microorganisms.

The UV lights used in HVAC systems are UV-C lights designed to act as germicidal lamps. Their short-wavelength rays break down genetic material in bacterial and viral cells, preventing them from multiplying. This makes UV-C very effective at disinfecting air and surfaces from pathogens like mold, mildew, bacteria, and viruses.

How UV Lights Clean the Air

Ultraviolet (UV) lights for HVAC systems are electronic air cleaners that are commonly known as ultraviolet germicidal irradiation (UVGI) systems.

They target a very specific type of air contaminant, namely microorganisms such as bacteria, viruses, and mold spores.

You might be familiar with the way hanging laundry out in the sunshine helps kill any germs or mold clinging to it. UV lights work in essentially the same way.

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UVGI systems produce the same kind of ultraviolet light that’s present in sunshine, but at a much higher intensity than found in the sunshine that reaches the earth. This light destroys microorganisms’ nucleic acids, damaging their DNA and either killing them or leaving them unable to reproduce.

The light affects only living microorganisms, meaning these systems can’t control dust, pollen, pet dander or other particles that aren’t alive. Gaseous pollutants, such as cooking fumes and volatile organic compounds (VOCs), aren’t affected, either.

UV light’s ability to kill pathogens in water and air was scientifically proven early in the 20th century. These systems have been used in hospitals as far back as the 1930s to reduce the spread of diseases such as measles and tuberculosis.

They’re now known to be effective against virus types such as rhinoviruses (common cold), influenza viruses (flu), and Severe Acute Respiratory Syndrome (SARS) and against bacteria such as Staphylococcus aureus (Staph infection) and Streptococcus variants.

The benefits are widely accepted, and thousands of water treatment plants, hospitals, and food handling facilities across the country use UVGI systems as part of their efforts to minimize contamination.

Not All UVGI Systems Work the Same

All that said, cleaning your home’s air isn’t as simple as sticking any UVGI air purifier you find into your HVAC air conditioning ducts. To be killed or neutralized, microorganisms must be exposed to the right kind of light for the right amount of time. A UV system’s effectiveness in a given situation depends on several factors, including:

  • Lamp wavelength and intensity
  • Number of lamps
  • Lamp position
  • Ductwork reflectivity

In addition, before you start looking for an HVAC UV light system, you’ll need to choose which of the two types available are right for your needs.

This is the most common type. It’s installed near the air conditioner’s indoor evaporator coil and shines constantly to prevent mold and bacteria from building up on or around the coil. Less mold and microbes on your coil means less in your air.

This system is specifically designed to kill microbes in your air. It’s usually installed in the return air duct and turns on only when the heating or cooling system is running. Because it purifies all the air passing through, it also reduces the risk of microbial buildup on your HVAC components, such as your evaporator coil, air ducts, air filter, and drain pan.

When a UV Air Purifier is Worth the Investment

While these systems do provide benefits and reduce allergens, they’re not cheap, and they require annual maintenance, which includes replacing the pricey lamps. The lamps lose power over the course of a year or two and eventually become ineffective at killing germs, even though they still produce visible light.

Before you invest in a UVGI system, consider whether or not your household has air quality needs that this air purification method can meet effectively.

If someone in your home is managing a respiratory condition, such as asthma, allergies, or chronic obstructive pulmonary disease (COPD) or has a weakened immune system, any additional air purification can pay off.

This is especially true of UV air purifiers, which target disease-causing microbes, not just irritants such as dust and pollen.

© Romolo Tavani / Adobe Stock

In a humid climate, your evaporator coil is at a greater-than-average risk of getting wet and developing mold. A UVGI system reduces the amount of active mold spores on the coil and in the air.

UVGI systems tend to provide greater benefits in more crowded conditions. UV light installation might be a good idea if you have a large family in a small house or even if you enjoy filling your home with guests during the autumn and winter holidays, which also happens to be the height of cold and flu season.

Because it controls a limited range of contaminants, a UVGI central air system alone isn’t enough to keep your home’s air clean. You’ll still need a higher-efficiency air filter to trap the smaller particles of dust, pollen, and other pollutants that can aggravate allergies and asthma.

If you’re considering having an HVAC UV light installed, talk with a heating and cooling technician first. A professional will be able to advise you on which type of system will do the best job of purifying your home’s air.

Frequently Asked Questions

Are UV lights for HVAC worth it?

UV lights can be worth it for some homes, but not necessarily for all homes. They are most beneficial if someone in the household has respiratory issues like asthma, allergies, or a compromised immune system. UV lights help reduce mold, bacteria, and viruses circulating through the HVAC system.

Plus, they can save energy, saving you money on your energy bill. They are also worthwhile in humid climates where mold growth on the AC coils is a concern. However, for an average healthy home in a dry climate, UV lights may not provide enough extra air-cleaning benefits to justify the initial cost and annual lamp replacements.

How much does it cost to install UV light in HVAC?

The average cost to install a UV light system for an HVAC system is $400-$1,000. This includes the UV lamp(s), power supply, installation labor, and any required duct modifications. Larger homes may need multiple lamps, which increases the cost.

Do HVAC UV lights use a lot of electricity?

No, UV air-sanitizing lights do not use a significant amount of electricity. The lamps typically operate on low wattages between 15–60 watts, so the electrical operating costs are very low, around $3-$12 per year.

How often should HVAC UV lights be replaced?

UV lamps gradually lose their intensity over time. Most manufacturer guidelines recommend replacing the UV lamps annually, even though visible light may still be produced. This provides maximum germicidal effectiveness. Some lamps may last up to 2 years before needing replacement.

Final Thoughts

Let me level with you – UV lights aren’t an absolute must-have for every home out there. But in my line of work, I’ve seen them make a real difference for families dealing with respiratory issues, allergies, or weakened immune systems.

These powerful lamps are a sharpshooter when it comes to taking out those microscopic pests like mold, bacteria, and viruses that love to hitch a ride through your HVAC/ AC system.

They’re also a lifesaver in humid climates where that pesky evaporator coil is practically begging for some funky mold to set up shop. Of course, if you’ve got a healthy household and the climate’s on the drier side, a top-notch air filter might just do the trick without the added UV light costs.

But if you do decide to hop on the UV light bandwagon, let me give you a friendly heads up – proper installation and yearly lamp replacements are non-negotiable. Sure, the lamps themselves are a low-wattage bunch, but those yearly replacements will put a small dent in your wallet.

At the end of the day, UV lights are just one weapon in the war against poor indoor air quality. They pack the biggest punch when you combine them with other heavy hitters like upgraded filters, duct cleaning, ventilation, and cutting off pollutants at the source.

My advice? Give your friendly neighborhood HVAC pro a holler, and they’ll let you know if UV lights deserve a spot in your air-cleaning arsenal.

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Reviewed for accuracy, cost data, industry best practices, and expert advice by Coty Perry.

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