UVC light has long been used as a disinfectant in industrial settings but, post-pandemic, there's been a proliferation of UV sanitising devices aimed at consumers. Most commonly, they’re sterilising boxes for phones and small tech but you can also buy larger box sterilisers, sterilising wands and sterilising lamps.

A recent study by the Office for Product Safety and Standards found that one in 20 consumers had recently invested in a product of this kind.

Which? quoted the Lighting Industry Association (LIA), which said that products had two types of failings: either the light they emit isn’t strong enough to properly clean items or they expose users’ skin and eyes to it.

The LIA said that some products do emit enough UV light to effectively kill germs but that stated cleaning times are often not long enough. The LIA also warmed that there is “no definitive third-party data” on how long it takes for UVC light to kill Covid-19.

UVC light sanitises by breaking down the DNA in micro-organisms, killing off bacteria and viruses on the surface of items. But it also has the same harmful effect on human and animal skin and eyes. This makes UVC light dangerous, causing damage to eyes and burns in the short-term. In the longer term, exposure can have carcinogenic effects.

Which? says that, as well as danger from the light itself, there’s a secondary risk. If users are over-confident about the efficacy of the sanitising product they’re using, they may not use other cleaning methods.

The organisation also released verdicts on various commonly available sanitising devices.

Sanitising wands

Which? has raised particular concerns over sanitising wands, which don’t tend to have a protective cover over the light. This means that they’re either dangerous or ineffective. It’s also not clear how long you need to expose an item to the light to clean it. The Which? verdict is to avoid wands.

UVC phone sterilising boxes

Which? calls these “potentially more viable than other UVC applications” but notes that there have been no studies to determine that long term use of UVC light will definitely not degrade plastic or other phone materials. Which? adds that Samsung has itself made a UV phone sanitiser but warns consumers that phones damaged by third-party UVC sanitisers won’t be covered under warranty.

The organisation said that larger sterilising boxes are “potentially useful” although it’s “hard to determine quality”.

UVC lamps

These freestanding lamps are supposed to be used to disinfect a room when it’s empty. According to Which?, many have poorly translated instructions and pose a danger if someone walks into the room while the lamp is on. It adds that there's "no certainty" about what the light can reach and therefore what will be disinfected. Which? characterises the UVC lamps as “not to be trifled with” and “not necessary”.

UVC appliances (including fridges and tumble dryers)

According to Which?, while these appliances are safer, as the light is contained, their main benefit is “likely to be psychological”.

UVC mattress vacuums

Which? says that these will probably only work on the surface of fabrics and bedding.

Overall, Which? is sceptical of UVC cleaning devices and urges consumers that traditional cleaning methods are still most effective.

Tech Advisor concurs with Which?’s safety findings. We do not recommend wand sanitisers and our reviews of UV sanitising boxes for phones and larger items provide information about product safety, such as light leaks.

We’d also say that if you buy and use any UV sanitising products, you treat them as one layer of protection and continue to keep washing your hands, cleaning your devices as usual and, of course, continue to follow Covid-19 protocols.

To find out more about how UVC sanitisers work, you can read our guide, and check out our round-up of the best UV sanitisers we’ve tested.