Written By Lester Mclaughlin
Updated On

Are you wondering if all the hype around UV lights for your HVAC system is worth it?

You’ve come to the right place!

In this Blue National HVAC guide, you’ll learn:

  • Why UV lights can be a scam
  • What you should consider before installing UV lights
  • The best way to keep your air quality in good shape

And much more!

UV Lights For HVAC Systems

So, if you want to know if UV lights for your HVAC system are actually worth it, keep reading our guide below!

If you’ve landed on this article, chances are you have an HVAC system and recently had a technician come in to service or repair it. They might have mentioned how UV filtration in your HVAC system is the be-all-end-all of air-scrubbing technology, how they can protect you and your loved ones, reduce allergies, and help keep you from getting sick.

You should be very happy to hear a tech tell you these things because it lets you know right away that they’re probably at your home just for the money and don’t genuinely care about high-quality work or service.

Recently, our HVAC team has heard stories about how UV lights in HVAC systems can help prevent the spread of COVID-19. With very little information available on whether or not this is true and to what extent they can kill off the COVID virus, we decided to dig a little deeper and write this article as a resource for any homeowner considering installing UV light in their HVAC equipment.

The reality is that UV HVAC filtration is the new technology that irresponsible or uninformed HVAC companies push on their customers, only it doesn’t really work all that well.

Let me explain.

Why Is UV Light Being Pushed By HVAC Companies?

The promise of UV lights in your HVAC system sounds amazing: “ultraviolet” sounds super advanced, and hey, hospitals use them to kill germs, right? Right. So what are they used for? Why consider them at all?

Well, to understand the appeal of UV lights, we need to have a very brief science lesson. I promise this will be quick.

UV radiation is naturally given off by the sun in three distinct wavelengths: UVA, UVB, and UVC. UVA is what’s given off by blacklights, and it’s harmless to humans. UVB is significantly more harmful, as it gives us sunburn and contributes to skin cancer. UVC doesn’t reach the earth because it gets absorbed by the ozone in the atmosphere. Good thing too, because it’s super harmful and causes skin and eye damage much more rapidly than UVB.

Since UVC doesn’t get past the ozone layer in our atmosphere, things like bacteria, viruses, and fungi haven’t adapted to being exposed to it. When they are, they die off.

This reaction to UVC is what makes people so excited about putting it in their HVAC system. The promises of these lights include effectively destroying all mold spores, viruses, and harmful bacteria that might be floating around in your home.

What Is an HVAC UV Light Supposed To Do?

Just like in a hospital setting, proper UV radiation can kill off the stuff you don’t want lingering in your indoor air. There are several points HVAC technicians will use to sell you on adding UV filtration to your system.

“They Can Eliminate Viruses!”

One of the claims that some HVAC companies make is that a UV light in your HVAC system can kill off viruses. Imagine keeping yourself and your family protected from the flu virus, common colds, and more. Sounds a bit too good to be true, if you ask me!

Most recently, UV lights have gained popularity because they’re said to be effective at killing the novel coronavirus, COVID-19. With these promises, how could you possibly turn down getting one installed?

Stay tuned.

“No More Mold In Your Indoor Air!”

Every homeowner worries about mold growth in their house. We’ve all heard horror stories like the one my friend lived through. He bought a house that had recently been renovated.

It turned out it was previously a foreclosure, and the bank was unaware that there was severe mold growth in the HVAC ducts. After about a month of living there, he had allergies and cold symptoms constantly, and he finally discovered the mold…and the inconvenience of a $5,500 remediation bill.

So, imagine a simple lightbulb that could forever eliminate airborne mold spores in your home! Sign me up.

But wait, there’s more!

“Be Gone, Bacteria!”

Finally, some sales-y HVAC techs swear by UV light treatment in your system because it can kill off bacteria. The company’s representative gets halfway through saying “Cladosporium cladosporioides,” and any homeowner will be biting their nails and hoping for a solution to keep this and other bacteria out of the air they breathe.

Why They Don’t Work

This all sounds amazing. BUT…the truth is…

UV lights in HVAC systems don’t provide all these benefits. In fact, they provide almost none of them.

How can this be possible? I’m glad you asked!

They’re Not Powerful Enough

Most importantly, the UV lights that most HVAC techs try to sell you on aren’t powerful enough to kill even a substantial number of mold spores, bacteria, and viruses circulating through your system.

I had a family member who worked as a hospital administrator who told me that a single UV light fixture for a hospital setting costs over $15,000 in some cases. Now, if a $15,000 light is required for killing germs in a hospital, what is that $700 light — which includes the labor for installation, by the way — going to do for your home?

You can get a super powerful UV light added to your HVAC system, but it’s probably overkill and will cost you thousands and thousands of dollars.

They Don’t Interact With the Air Long Enough

Another issue with HVAC UV lights that the sales-y technician won’t tell you is that the UVC radiation doesn’t interact with the circulating air for very long.

Air moves through your ducts at around 400-900 feet per minute in a residential system, depending on where you take the reading. UVC radiation works, but it’s not a miracle air treatment, and a single bulb is not even close to being able to purify the air moving at this speed.

In reality, most of the bacteria, mold spores, and viruses in the air will move very easily past the UV light without being affected at all. That means your air quality is hardly different before and after UV light installation. Even after you have UV bulbs installed, these contaminants will all circulate back into your indoor air, and you’ll still breathe them in…only you’ll have about $700 less in your bank account.

They’re Not Even Installed In Your Ducts…

And the last point, which is really the kicker, is that UV bulbs don’t even get installed in your ductwork most of the time. I’ll actually say that again: UV bulbs aren’t treating the air moving through your system.

Okay, some do. But most of the UV lights your HVAC company is trying to sell you on don’t go inside the ductwork. Instead, they’re set up to shine on the condenser coil and the drain pan.

This is the main reason why UV lights in your HVAC system very likely will not help prevent the spread of COVID-19. Researchers know that the virus travels in airborne water particles, so only UV lights installed in the ducts that treat the air flowing through would stand a chance of being helpful.

Even then, they’re unlikely to be strong enough or interact with the air long enough to kill the COVID viruses suspended in the air.

So, you’re paying a good chunk of money to have properly cleaned air for you and your family, and instead, the UV lights are shining on some random pieces of equipment? Yep, that’s right! That brings me to my next point…

What Do They Actually Do?

UV lights in HVAC systems aren’t totally useless. The ones that most HVAC companies push on their customers are underpowered and won’t treat air even close to the rate at which its moved through your system by your air handler.

However, they do provide some benefits.

The reason most get installed on your condenser coil and drain pan is that these areas tend to experience condensation. They stay moist when your HVAC system is functioning, making them prone to mold growth and even algae. Some bacteria also thrive in damp conditions, so these areas are kind of a catch-all for all nasty things in your HVAC system.

One thing I haven’t mentioned yet is that UV light, when used properly and set up with enough power, can eliminate contaminants in the air and on surfaces. You might already be putting the pieces together here.

When a UV light is set up to shine on your condenser coil and drain pan, it can be fairly effective at preventing mold and bacteria from inundating these pieces of your system.

And to be fair, mold spores and bacteria on your condenser coil could make their way into your air supply, so these UV lights do offer a very slight benefit.

Are HVAC UV Lights Worth It?

If you’re asking this, you definitely didn’t read anything above! But I respect your time, so I’ll summarize for you.

The HVAC UV lights your technician or HVAC servicer mention are more or less a scam.

Why? They’re touted for their ability to destroy mold spores, harmful bacteria, and viruses that work their way into your air supply, so they’re said to improve your indoor air quality and keep you safe from infection, allergy symptoms, and other medical issues associated with breathing them in.

However, the bulbs used in most residential systems are severely underpowered, don’t work quickly enough to kill stuff in the air that’s circulating through your ducts, and they typical aren’t installed in your ductwork, so they aren’t even meant to treat the air.

Instead, they help keep mold and bacteria from developing and thriving on your condenser coils and drain pan.

Now, you might be asking: is the cost of around $700 to install an HVAC UV light worth it just to keep these pieces of equipment clean?

Probably not, but let me break it down to be sure.

Cost of UV Lights Vs. Cost Of Routine Maintenance

Since UV lights only really work to keep your drain pan and coils free from mold and bacteria, let’s compare the price of each to see which is a better value for your money, especially since they both accomplish the same thing.

An HVAC UV light costs around $700-1,000 to have a professional purchase the unit and install it for you. You might pay less if your tech is selling you on a cheaper model. You’ll have to replace the bulb about once a year, which will cost about $300 each time.

Routine maintenance on your system, which will include cleaning and disinfecting of the condenser coils and drain pain, will cost an average of $150 each time, and it’s recommended that you get your system checked once a year.

The Bottom Line

Routine maintenance will cost about half of what replacing your bulb will cost, and you won’t have the initial outlay of $700 to install anything. Plus, routine maintenance accomplishes the same thing as UV bulbs and includes servicing of your entire system…not just the parts that a UV light would keep clean.

All in all, the UV lights your HVAC company is trying to sell you on are probably a waste of money, and you’d be far better off getting your system serviced manually once a year.

Meet Your HVAC Expert

Lester Mclaughlin

HVAC systems are highly technical and often is the most misunderstood part of the house. From ductwork to heat pumps, I've been exposed to all sorts of issues facing homeowners. It really irks me when a homeowner is given bad advice like refilling freon vs fixing a leak in the system. I'm here to help our website readers with their heating and a/c problems.
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