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Skeptical about UV light sanitizers? We put one to the test

We’re living in strange times, and the few things we know we can do to protect ourselves involve washing our hands and sterilizing surfaces and objects regularly. But who wants to waste all that paper or sanitizing wipes to clean our phones and other objects? Enter the growing popularity of the UV-C sterilizer. How do we know it really works? Well, we brushed off our 6th-grade science skills and put the Coral UV Sterilizer and Dryer to the test.

While many people are turning to UV phone-sanitation boxes to keep their devices clean, there are limitations. For starters, they can only sanitize a phone. On a good day, a phone is a huge germ collector, (it has been cited repeatedly that a phone has more germs than a toilet) and should definitely be one of the first things you sanitize. In fact, all high-touch items (think: Glasses, earbuds, iPad, remote controls, keys, etc.) should be cleaned/sterilized frequently as well.

The hypothesis: UV-C machines can kill germs on our devices

The Coral UV has all the certifications you’d want including EPA testing and FDA approval. According to the company’s co-founder and CMO, Titus Tse, “The UV-C light emits a UV-C ray at the correct wavelength that actually disinfects and kills the bacteria, viruses, and germs.”

Image used with permission by copyright holder

An independent lab tested the Coral UV using a variety of bacteria, and the results state that the device kills 99.9% of household germs. Impressive.

But what about the coronavirus? Can UV-C light kill the coronavirus? In theory, yes, because UV-C did inactivate both SARS and MERS. Tse says they haven’t been able to test the machine with the coronavirus yet because there are no samples available.

The experiment: Grow bacteria in a Petri dish

We decided to channel our inner 6th grader and went back to science class with the help of a Steve Spangler Science kit. We ordered the company’s Growing Bacteria Kit, which contains cotton swabs, six petri dishes, a plastic beaker, the nutrient agar, a shoe box, and an activity guide to help design the experiment. For all you parents looking for educational ways to entertain your kids, there are tons of science activities that you can do at home, and it provides everything you need.

For our test, we mixed up one teaspoon of agar with three ounces of water, and boiled it for about a minute until the agar dissolved. We poured enough of the mixture into the Petri dish to coat the bottom of it. We drew a line down the cover of the dish with a marker and labeled one side clean and the other dirty. We covered the dishes and waited an hour for the agar to cool and set up.

Image used with permission by copyright holder

With our dishes ready, we put the Coral UV to the test.

First, we used a slightly dampened cotton swab to swipe our freshly used phone (it had a full day: The bathroom, the store, walking the dog, lots of calls, games), then rolled the swab in a zig zag motion around the dirty side of the Petri dish. We did this with other items as well, including a bandana.

Next, weplaced the phone and bandana in the Coral UV. We did the same cotton swab process when it came out of the Coral UV and zig-zagged the swab on the “clean” side of the dish.

We put the dishes in the shoe box and placed the box on top of a cable box for some heat to encourage bacterial growth. Then, we waited for science to work its magic.

The result? UV light does what it claims

After 24 hours, we checked the dishes. There was a little something happening on the dirty side, but nothing to get to excited about. The clean side was unblemished.

We checked again two days later, and found more growth on the dirty side of both dishes. Nothing had appeared on the clean side. The phone dish had way more activity than that of the bandana dish. So there really is something to that whole “your phone is dirtier than you think.” After a week, the results persisted. Bacteria continued to grow on the dirty side, but nothing appeared on the clean side.

Image used with permission by copyright holder

We’re big fans of the Coral UV because of the incredible amount of convenience and peace of mind it provides during this uncertain time.  We’ve been using it for over a month on a multitude of items and our tech has yet to suffer any damage. We place our phone, keys, headphones, and masks in it daily. There’s enough room to place all of that in the box at once.

The key is to make sure everything is spaced out. If anything is placed on the bottom of the tray like a mask, we’ll run it again on the other side. Of course, we still wash our masks, but it’s nice to have that extra measure in place.

There are three other functions. Sterilize only lets you choose to sanitize for 10, 15, or 20 minutes, but Tse says 10 minutes should do the trick. There’s Dry Only mode if you just want to dry off something, but it’s not recommended for electronics. Finally, there’s a 24-hour Storage mode for items you want to keep in there overnight and sterilize. This option seems a bit much, but germaphobes might appreciate it.

Peace of mind convenience

The Coral UV is competitively priced at $169. Other models of similar size can be in the $200 to $300 range. If you’re someone who has a cleansing station set up in your garage to disinfect everything that comes into the house, it’s worth having around. The peace of mind is priceless, and you’ll use fewer sanitizing wipes.

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John Velasco
John is the Smart Home editor at Digital Trends covering all of the latest tech in this emerging market. From uncovering some…
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