In my opinion, it's just a blatant scam... But let's hear your experience and thoughts. Amazon is overrun with these products now...
I never even heard of these actually. I think that you would have to do some research to see if they are really effective or not. I for one, just don't even know. I think these are the things that are probably being overhyped but they might be somewhat effective as well. I would have to look to see if it is something that is really helpful.
We had already asked an electrical engineer on this matter and it is clearly a scam. He said that it is always input equals output so it cannot be that the input of electricity consumed is less but the output is greater. Those gadgets are just scams. Sadly the office of my husband has one like that which they bought for $300 which was installed for more than a year until they realized that their electric bill remained the same.
Yes, we have actually been lured to use one before. My husband and I were out in the mall at that time and he saw this promo regarding a device that could actually help lower the cost of our electricity by just plugging it beside the appliance you want to save from. It was really silly of us to have ever believed such kind of promo. We tried using it for around 3 months or so then decided to plug it out because there was never any decrease at all with our electricity charge.