Power factor correction devices improve power quality but do not generally improve energy efficiency (meaning they would not reduce your energy bill). There are several reasons why their energy efficiency claims could be exaggerated.
First, residential customers are not charged for KVA – hour usage, but by kilowatt-hour usage. This means that any savings in energy demand will not directly result in lowering a residential user’s utility bill.
yet some reviewers such as on http://amazon.com/dp/B07FSQTBTQ claim that it has saved them money.
What could be the reason? Is it that some electricity meters measure kVA, or that people who want to reduce their bills adopt other measures and incorrectly attribute savings to the device?