I tested power-saving devices that promise lower electricity bills - only one was legit

"they are too good to be true. Many of these units seem to be repurposed cases for rodent repellers, and coincidentally, many of those are also scam devices. I've bought quite a few of these to test -- and report to the relevant authorities -- and they're all junk. Plug these into your outlet and the best you can hope for is that they sit in the outlet and add a little to your power bill because of the LED lights on the front."

"Here's an example of such a unit, this one aimed at the UK market, but you'll find similar units for sale in all the usual places online. Even the plug itself doesn't conform to UK regulations. It tries hard to look authentic, with a fake testing number on the back. Even the plug itself doesn't conform to UK regulations. I recorded a video for social media about a similar device a few years ago that explains the issue with the plug."

Consumers seeking lower power bills face many scams marketing 'power-saving' plug-in devices that claim to improve energy use, extend equipment life, or prevent electrical waste. Those units often repurpose cheap designs such as rodent-repeller casings, include fake testing numbers, and sometimes violate plug regulations. Many are ineffective, add small loads from LEDs, and can be fire hazards. Practical alternatives include smart plugs and power strips that can actually reduce consumption, and accurate meters that enable monitoring. Testing and reporting fraudulent devices to authorities reduces risk. Monitoring appliance usage helps identify waste and lower bills through informed behavior.

Read at ZDNET