HVAC UV lights: do they work and are they worth it?

HVAC Logo IconBy Tom MoorAugust 1, 2023
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Indoor air quality is an important piece of the home comfort puzzle. An HVAC UV light helps you stay healthy by sanitizing the air moving through your HVAC system, reducing the mold and viruses distributed into your home’s air.

What is an HVAC UV Light?

An ultraviolet (UV) light emits powerful rays of energy that kill bacteria, fungi, and viruses. They are commonly used in both home and commercial spaces.

UV lights may look like futuristic lightsabers, but they’ve been used for almost a century. In the 1930s, hospitals used these lights to treat conditions like tuberculosis.

There are three types of UV radiation: UVA, UVB, and UVC. When you put on sunscreen, you’re blocking out UVA and UVB rays.

The third variety, UVC, is used in HVAC lights and lasers. UVC rays have the highest energy of the three, and they are the only rays powerful enough to kill microscopic germs.

How do UV lights for HVAC work?

UV light for HVAC systems is installed either in your air handler or in your ductwork. When germs move through the central air system, they eventually make it to the sanitizing light.

Once the germs are exposed to the light, they absorb the light’s UV rays. The UV rays disrupt the DNA of the germ. When bacteria or mold’s DNA is damaged, it will either die or become unable to reproduce.

There are two varieties of UV sanitizer lights. Coil sanitizing lights sit near your evaporator coil. Air sanitizing lights are placed in your return vents, which are part of your ductwork.

HVAC UV light model types

Between the two models of UV light for HVAC, the “better” option depends on your system and needs. Both work effectively and can help promote cleaner air.

Still, they differ in ways that could impact your buying decision. Coil sanitizing lights are great at keeping your HVAC system clean, but air sanitizing lights do the best job of cleaning the air itself.

Note that you need a central HVAC system to use either variety of light. If you don’t have central HVAC, alternatives like air purifiers or air scrubbers are worth checking out.

Coil sanitizing lights

Coil sanitizing lights look like long, thin fluorescent lamps. They are the more common and less expensive of the two varieties.

In an air conditioner or furnace system, the air handler is the component inside your home. Inside the air handler is an evaporator coil.

The evaporator coil holds the liquid refrigerant that cools your home. Since the coil comes in frequent contact with the liquid refrigerant and the bacteria in the HVAC system, it’s a breeding ground for germs.

When the evaporator coil builds up too much moisture and bacteria, it can corrode. This makes the coil less effective, which means your home isn’t as comfortable as it could be. The bacteria buildup can also harm your HVAC system.

This model of UV light is placed right above or next to the evaporator coil. The light helps keep bacteria and fungi from forming around the coil.

Coil sanitizing lights are usually kept on 24/7. You can buy them in single or dual-lamp units.

We recommend coil sanitizing lights if you enjoy taking on DIY projects. Coil lights are less expensive and easier to install than air sanitizing lights.

If you’re focused on keeping your HVAC system running smoothly, go for coil sanitizing lights. They can kill the germs and gunk sitting near your coil, helping you save on long-term repairs.

Still, air sanitizing lights are more effective at cleaning the air. If you have severe allergies, coil sanitizing lights may not be powerful enough to reduce your symptoms.

Air Sanitizing Lights

Air sanitizing lights are installed in the ductwork of your central HVAC system. They usually resemble coil sanitizing lights, but some models are horseshoe-shaped.

Return vents suck in air from each room, then send it through the central HVAC system. Air sanitizing lights alter the DNA of the germs soon after they get sucked through the vent.

Depending on how the air sanitizing lights are installed, they could be wired with your blower motor and will turn on and off in sync with your motor. These models are less popular than coil sanitizing lights, in part because they’re typically more expensive.

Air sanitizing lights treat indoor air quality problems better than coil sanitizing lights. Because air sanitizing lights clean air coming through the return vents, the air is sanitized as it enters your HVAC system.

If you have respiratory concerns, we recommend going with air sanitizing lights. With the higher price tag comes better air cleaning abilities and greater peace of mind.

Does a UV light for AC really work?

Since viruses and bacteria are microscopic, you can’t see a UV light at work. Though their cleaning power isn’t visible to the human eye, multiple studies suggest that UV lights kill germs at high rates.

In 2015, Duke Medicine published a study showing that UV lights killed 97% of antibiotic-resistant bacteria, or superbugs, in hospitals.

Plus, UV lights have been shown to work specifically for HVAC use. A 2001 study from the American Society for Microbiology showed that coil sanitizing lights drastically lowered the amount of living fungi in an office’s HVAC system.

Air sanitizing lights have a better reputation for killing airborne germs. Still, even coil sanitizing lights have been proven to tackle contaminants effectively.

Benefits of UV light HVAC

A UV sanitizing light is a great way to keep your family (and your HVAC system) healthy.

UV lights target germs that can worsen conditions like asthma and COPD. These lights can also kill off volatile organic compounds (VOCs), which cause odors like tobacco smoke.

Plus, both varieties of sanitizing lights keep gunk from building up and moving through your HVAC system. This cleaning power can keep your system running better and longer.

With a more efficient unit, you’ll spend less money on repairs and maintenance. That’s why UV sanitizing lights can be a helpful addition to any home with a central HVAC system.

Whether you want to maximize your HVAC system’s efficiency or keep the effects of allergens away, a UV light is a smart long-term investment. This cleaning tool can help your unit last longer and create a cleaner environment for your family.

UV light for HVAC cost

Type of Light Initial Equipment CostInstallation CostReplacement Bulb CostMonthly Energy Cost
Coil Sanitizing$60-300$100-225$10-60$15-30
Air Sanitizing$80-400$150-295$15-125$15-30

Air sanitizing lights are the most expensive of the two models. Since they have to be installed in your ductwork, the installation is more invasive.

Replacement lamp bulbs are an ongoing cost you’ll need to consider. Your UV light may have one or two lamps, and each bulb should be switched out every 6 to 12 months.

Thankfully, there’s no notable difference in energy costs between the two types of light. Neither should guzzle up energy or spike your monthly electric bill.

HVAC UV light installation

DIY aficionados, this one is for you: coil sanitizing lights can be safely installed at home. Opting for at-home installation can save hundreds of dollars, but it can be challenging.

One obstacle is that installation requires carving a hole into your air handler.

The hole must be the same size as the UV light, usually between 1.5 and 2.5 inches. An X-Acto knife can be a helpful tool for precise cutting.

The next step is to push the UV light through the hole you just made. Then, you screw the light into the air handler.

Finally, plug your light into an outlet. The standard 120 Volt outlet is compatible with most UV sanitizing lights.

It’s important to be precise when cutting the hole. If you’d rather not run the risk of damaging your air handler, you may want to leave the installation to an HVAC technician.

Unless you have lengthy HVAC experience, we don’t recommend installing air sanitizing lights at home on your own. There’s more room for error, and it can have a lasting effect on your system’s energy efficiency if it goes wrong.

Similar to coil sanitizing lights, air sanitizing lights involve cutting a hole in your ductwork. If the hole is too big, it creates a leaky duct.

Leaky ducts are problematic obstacles to your home comfort. When air escapes through the holes, your unit compensates for the loss by running longer.

When your HVAC system has to work harder, it leads to higher electricity bills. The extra run times could also wear down your unit, and it may need more frequent repairs.

Leaky ducts can also draw in germs from outside your HVAC system, like in your crawl space or attic. Poor installation can defeat the purpose of installing a UV light, so hire a pro if you have reservations about how to complete the work.

Do I need a UV light for my air conditioner?

When mold and bacteria wreak havoc on your home, an HVAC UV light can save the day. They can kill fungi and other contaminants for hundreds less than a whole-home air purifier.

A UV light for AC can keep your split system in check. The lights kill the germs that hide inside your HVAC system, helping the machine run at its best.

All in all, the right HVAC UV light can improve the quality of your indoor air and the functionality of your system. If you have a central heating and cooling system, the light is well worth the investment.

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