Power Factor Correction


Caution: If you are ever offered a "Power Factor Correction" device that fits on your electrical panel or subpanels it is probably a scam! Run away. Power factor correction is well known, but correction goes at the appliance, not at the meter, and unless your utility charges for power factor (never at a residence) you will not save money. Run away and call the police.

Here is one study we did on an actual installation of  "guaranteed" power factor devices. The conclusion: They did nothing but remove money from the wallet of the business owner.

Here is a paper on power factor corrections: Power Brick analysis

"Power Saver” Devices That Claim to Save Money by Correction of Power Factor.

For a formatted, printable version click here.

As electricity rates go up and people become more concerned with their own energy consumption, many unscrupulous companies continue to market bogus products to unsuspecting consumers which promise to lower energy bills, save energy, and be good for the environment. There are many good products which do these things. But there are products and companies that do nothing but take your money. This is unfortunate, as it leaves many legitimate companies competing on the same basis as scammers. It is very hard to figure out on the basis of advertising alone what is a legitimate offer and what is a waste of money. My personal advice is to ask around, find out whether the device you are looking at really works or not, and if you still can't make a good decision hire a qualified engineer to help you.

Many advertised products contain claims that they will work well for you and you will be happy with the performance and/or that they will save you money. Many of these claims are simply unverifiable. Many claims appeal to emotion rather than science or common sense. A simple search of the Internet will yield hundreds of thousands of results for energy-saving products that do not work.

I have compiled a list of what I have found to be the most used claims of very poor products. Those claims are italicized and are printed in bold. My opinion about each claim follows that claim.

Good luck in your quest to save money and electricity.

Here are my top claims that I have heard which are, in many cases, meaningless and unverifiable:

Saves an average of 23% electricity!

Saves what? Watts, Amps? Do I save money?


  1. Do they guarantee that you will save money? They can’t, because they don’t know. It is probably guaranteed against loss by attack of mutant rodents, except gerbils.

  2. The guarantee is only valid if you produce four years of weather data from the National Weather Service. (This is really part of one company’s “guarantee.”)

It’s “Green.”

My guess is that if you had a nickel for every time you heard that a product was “green,” you would have several dollars at least. This is a political word which has emotional meaning as we associate “green” with “good for the environment.” It may not really mean anything at all.

UL listed.

Underwriters Laboratories is an independent testing agency which tests for safety. Obtaining a UL listing on a product means that if used in the manner intended it will not explode, catch fire, or hurt you. Underwriters Labs does not test products to verify that the claims are true. Some manufacturers say that their product is UL listed when it is not. I have personally disassembled products with UL labels that if used in accordance with the manufacturer's instructions would cause a fire and/or a shock hazard. Some unscrupulous companies claim a UL listing when they have none. Buyer beware.

Used in the White House!

It’s a brick; they made a path through the garden. Completely unverifiable.

NASA tested!

They tested it all right; it works as a brick! Works great too, call NASA!

(Big Company) Certified!

Why would that company even care? If it really worked don’t you think they would have their own version for sale?

Used in buildings around the world.

Bricks have been used for centuries in construction.

Used in the East Burlingtown water treatment plant.

Where? Who should I call there?

Proven Technology!

What exactly is the “technology?”


Believe it or not, there are many patents for bricks, or improvements for bricks. There are dozens dating to the founding of the United States Patent Office. Just because you patent something does not mean that it works, and no, the patent office does not verify claims. It only examines for novelty, so unless your claims violate the laws of physics, you will get a patent.

Includes TVSS surge protection.

I guess the surge protection might be a good thing in some places. I’ve never suffered any damages from electrical surges either at home or at my office. The utilities that supply power have done a great job of supplying reliable clean power over the years and even though my office was next to a machine shop that was using electrical punches and arc welding equipment, I've never lost a piece of equipment to electrical surges. I do have surge protectors on all my computers. They are included in the power strips that I buy.

Makes motors run cooler.

There is no reason or evidence that this is true. Remember that you might be able to change the power factor in the wiring outside the motor, but the internal wiring of the motor will still see the same power factor. I did attempt to attach precision temperature probes to a motor casing and measure the temperature with the power factor correction turned on and then turned off. I noted no difference in temperature during this test, however learned later that the power correction device I was using was a fraud and therefore I could get no good information from my test.

Makes motors last longer.

This claim is completely unverifiable as industrial motors are designed to last many years. There is no reason to expect this to be the case. Keeping the shaft properly lubricated according to the manufacturer's recommendations will do far more.

Approved by the EPA, Department of Energy and the US government and is Energy Star rated.

Not true. Most government agencies have specifically warned about power factor scams. There are no Energy Star rated power factor devices, however there once was an Energy Star rated gasoline powered alarm clock.

We have testimonials from happy customers!

  1. “Confirmation bias” is the denial of disconfirming evidence. Psychologists say that this is a way of protecting our own ego when we learn we have been scammed.

  2. I just spent $3000 on an energy saving device! I’m motivated to save energy! Hey! Turn off those lights!

  3. Did you call those references? I tried once and the telephone numbers were dead ends! Most “testimonials” had no telephone numbers at all!

  4. You have testimonials. I have a watt-meter.

This technology was invented by Joe Smith and it is revolutionary.

  1. Joe Smith didn’t invent anything. Capacitors were invented in 1745. James Maxwell described the equations for electrodynamics in 1862. Thomas Edison built AC generators in 1882, and Elihu Thomson invented the recording watt-meter, which measures watts, not volt-amps in about 1883.

  2. Every electrical engineering student is taught in their junior year the proper use of reactive components (such as capacitors) to improve power factor in industrial applications, which can help to save money and improve efficiency. The book I used when I studied this was first published in 1966.

Our device corrects for bad power factor.

  1. Do you have bad power factor? Do you pay for it? Most customers do not pay any extra for low power factor. No residential customers pay for low power factor. Some commercial customers do, so they can save money.

  2. Reputable power factor correction companies will tell you that the power factor correction device(s) should be sized and switched. Do you know what you get when you apply power factor correction to a circuit that has a good power factor?: bad (low) power factor.

  3. Many appliances already have power factor correction in them, by statute. Consumer appliance manufacturers have been required to have power factor correction integrated for over 20 years!

  4. Power factor is very easy to measure, which is perhaps why this particular characteristic of steady-state AC circuits has been exploited so much. A simple watt-meter (less than $20) will read power factor. Power factor is also very easy to manipulate and change with a few inexpensive parts. A demonstration which changes the power factor dramatically with the addition of a few parts is indeed very impressive, but means nothing for most people because it is not part of their utility's billing statement.

Our engineer has figured out how to do save money, legally.

  1. If this really were true wouldn’t a whole lot of people be doing this, publishing the results and making a ton of money?

  2. Is this guy really an “engineer?” Or is he a crackpot, or some guy with an electronic meter showing us a great power factor demonstration.

Buy now and we will give you a steep discount!

We want your money as soon as we can get it!

It’s magic!

Magic is based on illusion, and when done well really makes you believe that what you are seeing is real, but it’s not.

A video proving the device works is on the Internet.

  1. I love the one where the guy has a motor and says “this motor is just like the one you have in your refrigerator.” Except the motor is not connected to anything. I’ve never heard of anyone buying a motor and not attaching the shaft to something.

  2. I once got my hands on one of these demos. It was riveted closed and I had to pry out the rivets with a screwdriver. Inside I found 20 feet of small gage electric wire, placed to make the demo work. It wasn’t real. It was a fraud.

  3. You can find videos on the Internet proving that cats can play chess.

We have financing, so it really won’t cost you anything.


You’ll have to pay BOTH the bank and the utility.


Don’t try to save money by buying something on a “one size fits all” basis. Make sure that the recommendations are explained to you in a way that you understand. If you feel uncomfortable with your advisor, move on until you find someone you trust. Have a qualified engineer do an analysis for your specific needs. Don’t be pressured. If you don’t want to pay a fair price for an assessment, turn off the lights, that works fine, or go to eBay, where you can buy an “energy saver” for as little as $4. Remember that anyone can make a claim for a device they want to sell you, and if that claim is unverifiable then they cannot be caught cheating you.

References for power factor analysis and for analyzing steady state AC circuits:

Here are some textbook references for those so inclined. I know the books are now out of print and quite old, but is was nearly 30 years ago when my formal training in power factor correction occurred in college. As it turns out both of these texts are now classics. The second book is currently in its 12th edition, and at $177 quite a bit more expensive than the first edition I purchased in 1983 for $18.

Smith, Ralph J. 1976. Circuits, Devices and Systems. Third edition, New York, New York, John Wiley and Sons.

Pearson, S. Ivar and Maher, George J.. 1965, Introductory Circuit Analysis, Huntington, New York, Robert E. Krieger Publishing Company.

Copyright notice:

This work is published without copyright. It is public domain. You are completely free to use any part for any purpose and do not need to attribute the reproduction to the original author. Please do not claim it as your own work.


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