Quick answer: No. Plug-in “energy saver” or “power factor” boxes that promise to cut your electricity bill by 50% to 90% do not reduce what households pay. Home meters bill you for real energy (kWh), and these devices cannot reduce the energy your appliances need. Consumer and trading standards bodies have repeatedly warned about them.
The ads usually show a small box with a light that you plug into any socket, testimonials, a “secret the power companies don’t want you to know” and a countdown discount. The box is cheap to make and often contains little more than a capacitor and an LED.
Why they cannot work
- You pay for kWh, not “reactive power”. The boxes claim to correct “power factor”. Large industrial users can be billed for poor power factor, but residential meters in the US and UK bill real energy, which a capacitor in a socket does not reduce.
- A box in one socket cannot change what other appliances use. A heater on the other side of the house still needs the same energy to make the same heat.
- Independent tests have found no meaningful saving, and some cheap units have raised electrical safety concerns.
How to spot the scam
- Promises of savings of 40% to 90% for any home.
- “Engineers” or “power companies hate this” stories, and fake news-style articles.
- No independent safety certification marks, or marks that cannot be checked.
- Countdown timers and “buy 3, get 2 free” bundles.
If you bought one, check your card provider’s chargeback rules, and report misleading ads to the Federal Trade Commission (US) or to Citizens Advice and trading standards (UK). Do not leave unknown electrical devices plugged in unattended.
What actually saves money
- Use less heating and cooling: thermostat settings make the biggest difference. See the best thermostat settings.
- Cut standby power with switched power strips. See phantom load.
- Measure your appliances with a genuine plug-in energy meter, which shows usage but does not claim to reduce it.
- Check your tariff and compare your rate with your state average or the UK price cap.
- Replace inefficient appliances when they need replacing anyway, such as an old fridge. See fridge running costs.
More: 25 ways to lower your electric bill.
A real example: what a “90% saving” would really mean
An average US home uses about 880 kWh a month. A 90% saving would mean cutting that to 88 kWh, roughly the energy used by a single refrigerator and a few lights. No device plugged into one socket can make your heating, air conditioning, water heater and laundry need 90% less energy, because those appliances turn electricity into heat or motion that has to come from somewhere.
If a gadget seems to work after you plug it in, check the kWh on your bill for the same month last year: weather, rates and billing days explain most short-term changes.
Legitimate devices that do save energy
- Smart thermostats and programmable timers, which reduce how long heating and cooling run.
- Switched or smart power strips, which cut standby power.
- LED bulbs, which use around 80 to 90% less electricity than incandescent bulbs for the same light.
- Plug-in energy meters, which do not save anything by themselves but show you where the energy goes.
More questions readers ask
Can I get my money back?
Contact the seller first. If that fails, ask your card provider about a chargeback, and report the advert to the platform where you saw it.
Are these devices dangerous?
Some cheap units have been found to have poor internal construction. Do not leave an unknown device plugged in unattended, and remove it if it gets warm or smells of burning.
Sources
- U.S. Federal Trade Commission, consumer guidance on energy-saving claims and how to report scams.
- Citizens Advice (UK), guidance on scams and reporting misleading products.