Do Whole House UV Air Purifiers Work?

Air purifiers have gained popularity in the last three years owing to the Covid-19 pandemic. More people are now conscious of their homes’ air quality, and air purifiers like the UV-type are trending. So, does a whole-house UV air purifier work as it says on the description box?

Whole-house UV air purifiers work by inactivating microorganisms, making the air in your home a little healthier. However, their effectiveness is minimal because of how UV light works. Also, they do little, if anything, against harmful particles and gases.

This article explores what a whole air purifier is and if a whole-house UV air purifier works. I also review whether air purifiers with UV light are worth it and the cost of a whole-house UV air purifier.

What Is a Whole House Air Purifier?

The US Environmental Protection Agency (EPA) says specific pollutants are two to five times more concentrated indoors than outdoors. Knowing this brings a certain level of awareness and concern about the quality of the air you’ve been breathing at home. 

A whole-home air purifier is an air purifier that cleans and freshens air throughout the house at once. Unlike a portable air purifier that tackles one or two rooms at a time, this one purifies your home’s entire air. 

The boundless space that this purification system covers is one of its selling points, and it is ideal for homes, especially large ones. Every corner of your home receives fresher, cleaner air with these purifiers. 

How It Works

A Whole-home air purifier installs directly into your HVAC—the return-air ductwork – and works hand-in-hand with it. Each type of purification system cleans and uniquely freshens the air, but all work in a general pattern. 

When you turn on the HVAC (heating or cooling unit), fans bring air into the vent. The system cools or heats the air as it passes through the ductwork, and the purification device removes pollutants. Clean air circulates back towards the vents, blowing into the rooms of your home.

Types of Whole-Home Air Purifiers

Air purifiers use two major types of filters: electronic filters and media filters. Media filters create a physical barrier to trap minute particles, while electronic filters use high-voltage charges. Some filters combine both techniques, and others add activated carbon to absorb odors.

Here’s a description of the different types of whole-home air purifiers:

Flat filters: These are higher-standard filters you fit onto your HVAC handler. Flat filters are better than regular HVAC filters, and they can remove more pollutants. They keep out dust and large particulate contaminants but aren’t effective against finer particles, gases, volatile organic compounds (VOCs), or smells.

You’d have to replace the filter every three months to prevent it from clogging up and straining the HVAC fan. If your HVAC can’t handle filters with a MERV rating above 10, don’t use such filters.

Extended media filters: They are a thicker version of flat filters and comprise several stacked layers of filters. Stacking the filters next to each other slows down the movement of the pollutant, increasing its chances of being trapped and removed. 

You’d need a professional to fit them since they must enter your HVAC ductwork to trap particulates before they enter your house. These filters last longer than flat filters, and you only replace them once a year. Extended media filters don’t need electricity to provide you with cleaner air.

Electrostatic/ionic air purifiers: This is the first actual air purifier on this list, and it creates negative ions using an electrical charge. The charge traps air pollutants, and together with the negative ions, it rests on the metal. Ionic purifiers run at a low cost, but you must clean the metal plates frequently.

Ultraviolet Germicidal Irradiation purifiers (UVGI): They use UV light to destroy bacteria, germs, and other microorganisms. You can connect the device along your air duct or on your air handler. Alternatively, you can get it in combo with other types of air purifiers, as a single whole-home air purifier unit.

APCO air purifiers: Advanced Photocatalytic Oxidation (APCO) air purifiers are pretty common and are effective without combining them with other types. Using UV light and a thin metal catalyst, they absorb and oxidize pollutants into carbon dioxide and water.

These air purifiers can handle particulate matter and gases, unlike the others. It uses a reaction chamber instead of filters, and you’d have to replace the chamber every two to three years.

HEPA whole-house air purifiers are also an excellent choice for your home. A combo whole-house air purifier combines the strengths of one or more types of air purifiers. For example, there are APCO plus activated carbon cleaners that work wonders for your home’s air quality.

Do Whole House UV Air Purifiers Work?

UV (ultraviolet) light has a long history as a disinfectant for surfaces, the air, and water. Like all air purifiers, UV air purifiers aim to decrease indoor air pollutants and deliver cleaner air. You may also know them as UV germicidal irradiation (UVGI) air purifiers. 

Most of the UV air purifiers on the market come as systems installed into pre-existing commercial or residential HVAC units. This means there are more whole-house UV air purifiers than stand-alone devices.

How UV Air Purifiers Use UV-C Light

UV-C light is the shortest wave (100-280nanometers), with photons that carry the most energy and vibrate the fastest. UVGI air purifiers use UV lamps to inactivate airborne microorganisms and pathogens such as viruses, mold, and bacteria.

This light has more energy than visible light, and it can change the structure of any molecule that absorbs it. DNA is especially susceptible to the alteration from UV-C light and, with enough damage, a bacterial cell can self-destruct. 

The emitter material (e.g., quartz) determines the light’s color (bluish or invisible to the human eye). According to the EPA, most residential units use mercury lamps that release UV-C light at 254nm wavelength.

Whole-house UV air purifiers combine a HEPA filter and a forced-air system. The UV-C emitting bulbs in the chamber briefly disinfect ambient air forced through the HVAC unit.

The Efficiency of UV Air Purifiers

Several factors affect the efficiency of UV air purifiers, including:

  • The high light dosage required.
  • Whether the microorganisms encounter UV light.
  • The duration of contact between the pathogens and the UV light.
  • Temperature and humidity—whether the cooling effect of airflow inhibits the UV light.

UV air purifiers may sound excellent in theory, but the reality often falls short of your expectations. Although UV-C light can kill pathogens like viruses and bacteria, it doesn’t have sufficient contact with the air to be effective.

In essence, the other part of the whole-house air purifier (the filtration unit) is more likely to rid the air of pathogens along with the other pollutants. Here’s a detailed look at how a whole-house UV air purifier handles air contaminants:

UV Air Purifiers Against Allergens

UV air purifiers are often ineffective against toxic gases and many solid particles. Allergens, pet dander, chemical fumes, molds, dust, and cigarette smoke can bypass UV purification, and it doesn’t remove them entirely.

Deactivated mold particles can still cause allergies, so even UV air purifiers may be an ineffective “protection” against asthma and allergy triggers.

UV Air Purifiers Against Microorganisms 

UV purification can deactivate mold and bacteria and reduce their spores. Since mold and bacterial spores are resistant to UV radiation, it takes a high dosage of UV light.

A whole-house UV air purifier doesn’t emit such a high dosage, and the air isn’t exposed to the air for a long time. Ambient air passes through the unit in a few seconds, and it’s just not enough for the UV light to handle the microorganisms.

UVA Air Purifiers Against Volatile Organic Compounds (VOC)

Common household products like paint or cleaning and disinfecting solutions emit these toxic gases. UV light can’t destroy VOCs. Instead, the light’s intensity can cause these household products to release VOCs faster than they usually would.

Fortunately, whole-house UV air purifiers come with a filter media to trap particles and do some air-cleaning of its own. In summary, your whole-house UV air purifier will work, but the UV light won’t be doing most of the work.

Are Air Purifiers with UV Light Worth It?

Getting clean indoor air can be challenging, as the air is a melting pot of solid (dust) and gaseous (CO2 and VOCs) pollutants. Coupled with airborne pathogens like viruses and bacteria that live on various surfaces, there’s a lot to clean up.

Since you cannot risk long-term exposure to these substances, it makes sense to use a device that can eliminate them all in one go. Air purifiers with UV light seem to be the answer you seek, but are they worth it? I have explained how UV light air purifiers work in the section above, so you know their effectiveness.

To weigh their worth, here are some limitations and disadvantages of air purifiers with UV light:

  1. UV light has no effect on particulate matter like ultrafine particles (UFPs) and PM2.5. Without a robust particle filtration system to work with, dangerous pollutants will remain in your air.
  1. Viruses and bacteria need extended periods of exposure to UV light before they’re inactivated, usually for several hours. UV rays can’t make any difference since the air flows too fast through the purifier.
  1. Ground-level ozone is a by-product of many air purifiers with UV light. Some UV air purifiers can produce heat, which converts free-floating oxygen molecules (O and O2) and water to ground-level ozone (03). This ozone is dangerous, with short-term exposure causing various respiratory symptoms.
  1. Brief exposure to UV light can damage your eyes and skin and even cause cancer. Despite the UV light being encased in the purifier, using such air purifiers is still a risk.
  1. UV air purifiers only inactivate bio-contaminants instead of removing them like other air purifiers. The UV air purifier system releases these organisms into the air in a viable but non-culturable (VBNC) state. This means that many of these particles can become infectious again if the right environment or situation “wakes” them.

For their weak efficiency against most air pollutants, air purifiers with UV light aren’t worth it. The UV light in them poses significant dangers to your health. Moreover, these cleaners are only effective in combination with other air filtration processes.

No matter how intense the UV light is, air passes through the purifier in a few seconds, and that’s not enough to remove microorganisms. At best, air purifiers with UV light lightly disinfects the air, and it’s an exaggeration to say they purify the air.

If you must buy a UV light air purifier, get high-quality models. Inexpensive models may have inadequate UV light technology, and it takes intense light to damage pathogens. Also, look out for UV light purifiers with multiple settings, multiple stages of air filtration, and noise reduction.

How Much Is a Whole House UV Air Purifier?

The cost of a whole-house UV air purifier depends on a few factors, including:

  • The size of your home
  • Installation or labor costs
  • Extra guarantees or warranties the device comes with

Whole-house air purifiers generally cost from $400 to $4000, with a national average of $2,230. If you want air purifiers with hospital-grade purification systems, it’ll cost $10,000 or more.

UV light filters alone cost $200 to $400, and installing them costs $400 to $800. A hybrid UV light system costs from $1,200 to $3,000. You’d need to replace bulbs annually, and they usually cost $20 to $70. 

For context, a hybrid system combines the particle capturing function of a mechanical filter with the germ-killing capacity of UV light.

Many air quality specialists will advise you to install whole-home UV lights close to the evaporator coil of the cooling unit. The evaporator coil becomes a natural breeding ground for mold in summer because condensation covers the coil. 

Once mold starts growing on the evaporator coil, air blowing over the coil can carry spores into all rooms in the house. UV lights are somewhat effective against mold spores, so situating them near the evaporator coil will prevent mold formation.

Whole-house UV air purifiers are beneficial for people with breathing problems. If you’re satisfied with the cost and functioning of UV-air purifiers, they can be a good addition to your home.