Lifx’s smart head that kills bacteria works, but here’s the small print

The Lifx Clean is a new smart light bulb with an intriguing twist. Not only is it a fully functional color-changing light bulb, but the company also claims to be able to disinfect surfaces and the air around it. The Lifx Clean, first announced in August, is now shipping for $ 69.99 to pre-order in the US, with large availability planned for spring.

Lifx has a variety of scientific studies as well as its own laboratory tests to confirm its claim that the Clean is the ‘world’s first antibacterial, germicidal smart light’. But can the light bulb work just as well in the average home as in the lab?

It is no coincidence that Lifx announced the light bulb in a year in which we all had to pay more attention than ever before to keeping ourselves and our homes clean. David McLauchlan, CEO of Lifx, says the company started talks in early March about developing a product like Lifx Clean, the same month COVID-19 was officially declared a pandemic by the World Health Organization.

“We’ve seen the alcohol companies make hand sanitizers and clothing companies make face masks, and I told the team that we can not do these things, but we make light,” McLauchlan said in a call. “There’s this technology there, why do we not investigate it and determine if we can do it?”

The “technology” McLauchlan refers to here is a very specific type of blue light with a wavelength of about 405 nm. This high-energy visible (HEV) light has been shown in a number of studies to “inactivate” a variety of bacteria (read: kill), including salmonella, E. coli and methicillin-resistant staphylococcus aureus (also known as MRSA) in laboratories. based studies.

Other experiments have used it in real-life situations such as hospitals. In three studies conducted between 2010 and 2013, researchers found that the lights reduced the number of bacteria on surfaces that were frequently affected in the hospital’s burn unit. The reduction varied greatly – between 27 and 90 percent – even within these individual studies, depending on factors such as how many days the light was used, and how much activity there was in the room where it was used.

The Lifx Clean incorporates this technology into a household light bulb via a series of eight 405 nm LED lights, which sit next to the standard red, green and blue diodes you find in Lifx’s other light bulbs. The array then has a typical distributor over it, which means it looks almost identical to a standard Lifx light bulb.

It’s benign in appearance – very different from any other light cleaning technology that became popular during the pandemic era: UV light. Pilot programs used UV light to clean subways, buses and aircraft cabins, and Transport for London rolled it out to disinfect escalator handrails.

UV works fast, but it is also incredibly dangerous if used incorrectly. This is according to Jim Malley, a professor of civil and environmental engineering at the University of New Hampshire, who has been studying the use of UV and other light as a disinfectant for more than thirty years. It can cause erythema, the skin redness mostly associated with sunburn, and repeated exposure have even been linked to skin cancer, he says. The light is especially harmful to the cornea of ​​your eye, and exposure to it can “give you the worst headache you could ever imagine.” Although your cornea can generally recover after being exposed to UV, Malley tells me, repeated damage “appears to be related to early blindness.”

By comparison, HEV light does not have the same problems. “Blue light, 405 nm, does not have that kind of energy,” Malley explains.

HEV light has its own disadvantages. Most importantly, the effect of light on bacteria has been studied as much as UV. Much of the research that has been done has focused primarily on the ability to kill bacteria, and there is less evidence to suggest that it is effective against viruses. This is a very important reservation, as COVID-19 is caused by the coronavirus SARS-CoV-2 – a virus.

Lifx is not ashamed to point this out. In its announcement for Lifx Clean in August last year, the company explicitly stated that “there is currently no claim that the product is effective in an antiviral capacity of any kind, including SARS-CoV-2.”

“I really want to emphasize that we are not trying to sell it as a ‘coronavirus killer,'” McLauchlan warned.

But Lifx still thinks that a disinfectant light bulb, even if it is antibacterial rather than antiviral, could help in an era of a global viral pandemic. Bacterial infections can nevertheless cause serious complications for anyone who is sick with a virus.

HEV lights are not very fast when used to kill bacteria. A 2009 study found that it took 405 nm of light as much as 60 and 90 minutes to deactivate almost all the bacteria tested, despite the fact that the light was a total of 2 cm away. . Hospital studies have focused on using the light continuously during daylight hours from eight to 14 hours or longer to achieve the desired bacterial reduction. By comparison, UV light can kill many bacteria and viruses within seconds.

These disadvantages mean that HEV lights are not really disinfected, despite the research that supports them, Malley tells me.

‘It’s not competitive, but not practical. You just can not have hours and hours of contact time, ”says Malley. In a world where a UV light can disinfect a phone within 60 seconds, 405 nm light cannot compete.

Lifx has a report on The edge of the tests of light against E. coli and MRSA, which showed how light performs at periods of two to 12 hours at different distances. While the Lifx Clean can kill more than 80 percent of the E. coli bacteria on a glass surface within two hours under the right conditions, you must use Lifx’s Clean lamp for up to eight hours to achieve a similar death rate for MRSA.

The time to kill bacteria is a disadvantage, but McLauchlan argues that the schedule functions of the smart ball mean that you can have it inserted automatically if you are not in the area. “You can literally burn at midnight that everyone is in bed and stays in the disinfectant until 6am and provides a disinfectant in that room or on that surface,” McLauchlan says.

The efficiency of the light also decreases the further it is from a given surface. The above results were obtained by keeping the light bulb just 40 cm away from the bacterium, placing it approximately at a table lamp height. Move the light bulb further and it usually takes longer to kill the same amount of bacteria. Even after eight hours, Lifx’s tests showed that the light bulb killed only about half of the MRSA bacteria on an area four feet away, or just over 65 percent of the E. coli.

These results mean that you are unlikely to see a big impact if you expect to use the Lifx Clean as a guide. Instead, the company sees people using the light bulb in accessories above desks and other surfaces. To his credit, Lifx is upfront about these limitations, and these test results are available on the site for all to see. If you are planning to pick up one of the light bulbs, it is worth reading it to understand where and for how long you need to run the light bulb to get an effect.

But there are other disadvantages to using HEV light that are unlikely to overcome smart planning or smart placement. Lifx, for example, initially said that the Lifx Clean could disinfect the air around the light bulb. However, the slow disinfection time makes it a fairly difficult performance, Malley explains because of how air particles tend to move around.

“They will not be able to keep the air particle blue long enough,” says Malley. If bacteria get really close to the blue light, you can see a reduction, he speculates, “but overall I do not think it can compete, because you just can not keep the air long enough near the death zone.”

There are all sorts of variations in people’s homes that can affect how reliably the ball kills bacteria. Disinfection of light is, by its nature, a line-of-sight technology, so that any shadow will not be disinfected, and any lampshade that does so will limit its effectiveness. One of the 2013 hospital studies found that light killed an average of 15 percent fewer bacteria on the side of a room that was indirectly illuminated compared to the areas directly below the ceiling lights. Nor can it penetrate deep into porous surfaces, McLauchlan admits.

The amount of variation in the average home may mean that Lifx quotes from its lab tests do not exactly match the real world. For reference, all of the above test results caused the bacteria to sit on a glass plate. It may work for non-porous surfaces such as kitchens or bathroom tables, but Malley warns that trying to generalize from laboratory results like this to the average home may end up looking ‘fairly unrealistic’.

Variations like these between laboratory results and how people use products in the home are nothing new, says John Coia, a clinical microbiologist and professor of clinical microbiology at the University of Southern Denmark. Coia was co-author of several actual studies that found that HEV light can reduce the amount of bacteria when used in hospital settings. He points out that many people may not even use the right concentrations when it comes to traditional chemical disinfectant.

‘You can argue about whether people use the right concentration [of HEV light], but do people use disinfectants at the right concentration? The answer is that they probably do not, ‘says Coia. “In many cases, they probably use concentrations that are actually sub-lethal.”

Everyone we spoke to, as well as Lifx, agreed that the Lifx Clean would not replace any normal detergent. But if you use it correctly, it can be an extra tool in your cleaning arsenal. ‘I would not see [HEV light] as a substitute for cleaning, but as a supplement, ”says Coia.

Several studies have shown that HEV lights like the Lifx Clean can kill bacteria under the right conditions. But even Lifx’s own lab tests have shown the limitations of the technology. It needs enough time, it needs to be at the right distance, and it needs a direct line of sight to bacteria to kill it. Lifx’s germicidal smart light ‘is not snake oil, but neither is a silver bullet that can save you from your weekly cleaning work.