UV light and the coronavirus: Big Ass Fans might have a solution

The ceiling fan uses UV lights to kill up to 99.9% of a room's airborne pathogens in minutes. It's now being tested against the virus that causes COVID-19.

Ry Crist Senior Editor / Reviews - Labs
Originally hailing from Troy, Ohio, Ry Crist is a writer, a text-based adventure connoisseur, a lover of terrible movies and an enthusiastic yet mediocre cook. A CNET editor since 2013, Ry's beats include smart home tech, lighting, appliances, broadband and home networking.
Expertise Smart home technology and wireless connectivity Credentials
  • 10 years product testing experience with the CNET Home team
Ry Crist
5 min read
Big Ass Fans

For years, doctors and health professionals have been using ultraviolet light as a disinfectant. Now, a major ceiling fan manufacturer is mounting UV lights onto the base of its smart ceiling fans, and promising they can rid a room of viruses and bacteria within minutes.

The company is Lexington, Kentucky-based Big Ass Fans, best known for its eponymous industrial ceiling fans, and the maker of the luxurious Haiku line of smart, app-enabled residential ceiling fans. Earlier this year, the company rolled out a new "uplight" accessory for those Haiku models that casts decorative light up onto the ceiling. Then, when the pandemic hit, the company thought back to 2011, when it teamed with an architecture firm to equip a hospital in Rwanda with ceiling fans to help improve the efficacy of wall-mounted UV sanitizers used to kill pathogens like tuberculosis.


A Haiku ceiling fan equipped with virus-killing UVC lights.

Big Ass Fans

It was your classic light bulb moment: What if that uplight was a UV sanitizer, with the ceiling fan pulling air up into its disinfection zone? With a head start on the legwork, the company scrambled to action.

"Mid-March, all of a sudden, it's kind of, wait a minute, we're already working on an uplight," says Big Ass Fans spokesperson Alex Risen. "And yeah, we put about four months of additional research and engineering to make sure that we're doing this the right way, but we were already 90% there.

"Sometimes in product development, it's better to be lucky than good," Risen admits.

Now, after an initial batch of independent lab-based tests, Haiku ceiling fans equipped with UV lights are available for order -- the first smart home product designed specifically to combat the spread of COVID-19. With the UV lights adding $500 to the already ceiling-high price tag (standard, non-UV models start at about $1,250), they won't come cheap.

Compelling claims

"Seamlessly integrated atop the fan, Haiku's UVC fixture directs invisible light upward, killing up to 99.9% of viruses, bacteria, mold, and other harmful airborne agents that pass through the disinfection zone," the company promises. "Haiku's powerful air mixing improves circulation within the space, bringing more pathogens into the disinfection zone and halting the spread of disease."

That's quite the claim -- but the science is sound. UV light from the sun is the environment's primary germicide, something scientists were documenting as early as 1877. Hospitals have been harnessing that power for years, with special UV lamps and wands used to sterilize rooms and equipment. This year, airlines, cruise ships and other businesses have begun using a variety of UV systems to sanitize common spaces.

The invisible light isn't practical for use in homes and around people, because direct exposure is dangerous for eyes and skin -- but that's where the ceiling fan approach seems to make sense. With the UV light source sitting above the fan blades and shining up towards the ceiling, there's no risk of exposure for anyone sitting below. Big Ass Fans says that it always adheres to any applicable certification standards required for legal sale and consumption, and that the Haiku UVC is no different. The company adds that the lights are programmed not to shine when the fan is off, which allows for safe cleaning and maintenance.

"We would say if you want to run it 24/7, we have 100% confidence in running it 24/7," Risen says. "The only impact is a positive impact in that it would continue to kill pathogens."

Early testing looks promising. In April, the company hired a team of third-party researchers from Intertek to study the fan's effectiveness. The researchers installed it in a 1,000-cubic-foot test chamber, then released a small amount of phi X 174, a bacteriophage commonly used as a stand-in for deadlier pathogens in tests like these. After 10 minutes with the Haiku spinning overhead, the researchers removed a petri dish from the room, let it sit overnight, and then compared it with a petri dish from an identical chamber with no fan at all.

"We actually got a 99.9% kill rate within 10 minutes," Risen says. "And they know that [phi X 174] is a great surrogate for most things that are difficult to kill in the air. So if it does well against this, your confidence is that it's going to do well against other stuff, too."

Watch this: Make your own gadgets to protect you from coronavirus
Enlarge Image

A transmission electron microscope captured this image of the SARS-CoV-2 coronavirus, which causes COVID-19.


But can UV light kill COVID-19?

We don't know for sure, but there's good reason to think that the answer is yes. UV light has already been proven effective against influenza and against other kinds of coronaviruses, including the ones that cause SARS and MERS. Researchers at Columbia University were recently able to kill 99.9% of exposed airborne coronaviruses like those using low doses of low wavelength, "far-UVC" light that isn't strong enough to penetrate human eye or skin tissue. Just recently, a study published to the preprint database medRxiv on June 26 and currently awaiting peer review found confirmation that UV light kills SARS-CoV-2, the virus that causes COVID-19.

Not all UV light is created equal. There are actually four kinds: UVA, UVB, UVC and vacuum UV. The one you want for disinfecting purposes is UVC, the wavelength for which falls between 100 and 280 nanometers. Exposure to UVC light in the right dosage and at the right wavelength can damage the DNA and RNA in organic cells, which stops them from replicating (and don't worry: UVC light from the sun gets completely absorbed by the Earth's atmosphere).

Most medical-grade UVC applications seem to zero in on 254 nanometers as the target wavelength for close-contact disinfection, but Big Ass Fans dials the diodes up a little higher.

"The sweet spot that we're looking at is UVC, specifically 260 to 270 nanometers," Risen says. "We're pretty much always right in that 265 range, right in between."

We'll know soon if the company's math checks out. Last week, Big Ass Fans began a new round of tests with Innovative Bioanalysis, a certified safety research laboratory in California. The tests will be similar to before -- but this time, they'll be testing for efficacy against the virus that causes COVID-19, not a man-made stand-in. 

Big Ass Fans expects the results from those tests later this month.


Big Ass Fans' less expensive Haiku model, the L Series, doesn't yet support the UV light attachment.

Ry Crist/CNET

What's next?

"We have certainly talked to some schools," Risen tells me, describing how the fans might be useful for sanitizing classrooms in the minutes between classes, when students are changing rooms. "The conversation is, 'Can they use CARES Act money to purchase an active air disinfection system?'"

The company is in talks with Kentucky's horse-racing industry, too, and looking into ways that the fans might be used to help sanitize places like guest suites and skyboxes between events. Big Ass Fans adds that a number of businesses across the country have already placed orders.

"One of the most recent places was a climbing facility in Seattle," Risen says.

But at $1,750 or more, it's difficult to imagine this fan making its way into many homes. And, notably, Big Ass Fans isn't bringing the UV technology to its less expensive "L Series" line of Haiku smart ceiling fans. The UV lights aren't available as a retrofit attachment for existing fans, either.

"It's unlikely we'll add it to the Haiku L," Risen says. "Future options allowing for a downlight and a UVC above motor would be more what we're targeting."

In other words, don't expect to see a version of this fan that doesn't cost upwards of $2,000 anytime soon.