"Still not convinced?

One of the more surprising comments I have received lately was that this kind of analysis is "Rubbish" or that it doesn't address the "fact" that some acquaintance of theirs is saving money using a power factor correction device. This is unfortunate. I don't dispute that you may have seen a reduced power bill, just the "fact" that this reduction is due to the "device" and not other factors that were overlooked.

Electrical theory is not some "theory" that might or might not be true. This is an area that has been well understood for more than a century and concepts like resistance, impendence and reactive current are accepted as reality -- something which you ignore at your peril. Even if future understandings of particle physics were to give us new insights to old laws -- these old laws are for all practical purposes, perfect for predicting an outcome in household situations.

Despite this, people install devices like this and become convinced that any reduction in their power bill is due to the device. Remember that if you want to test something like this with the intention of proving that it defies our current engineering knowledge, you are going to have to use calibrated test equipment and carry out carefully controlled experiments. The temperature (degree days) vary greatly from year to year, habits change (longer or shorter showers) and a host of other things will vary your monthly power bills significantly from any chosen month from one year to the next. Even thinking about your energy saving device causes behavior changes -- like turning off lights when you leave a room, running the water less, etc. Therefore, your monthly power bill is in no way a controlled experiment, and the savings you are hoping to measure are very small compared to regular variations. Comparing power bills is useful, but only verifies significant savings such as switching from electricity to natural gas, changing high flow to low flow shower heads or other major changes.

If your experiments lead you to conclude that you actually save significant percentages of power using one of these devices, you need to re-evaluate your controls. Since these results would be violating the laws of physics, nobody will believe them unless they can repeat them. If nobody can duplicate your results (which is extremely likely) then you must re-evaluate your experiment. Finally, very few people who can set up a proper experiment are going to be willing to spend their hard earned money to purchase a device and then spend time conducting an experiment to prove that their purchase was a waste of money. And even if they did, would you believe them?"*

*http://www.nlcpr.com/Deceptions1.php

The following is from ENERGYSTAR

ENERGYSTAR Q&A

Do Power Factor Correction Devices (sometimes called Amp Reduction Units or KVAR) really save money? Can they earn the ENERGY STAR label?

ENERGY STAR does not qualify any Power Factor Correction Devices. Please send us an email at [email protected] if you see one that claims to be ENERGY STAR certified.

Power Factor Correction Devices claim to reduce residential energy bills and to prolong the productive life cycles of motors and appliances by reducing the reactive power (kVAR) that is needed from the electric utility.

We have not seen any data that proves these types of products for residential use accomplish what they claim. Power factor correction devices improve power quality but do not generally improve energy efficiency (meaning they won't 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. Second, the only potential for real power savings would occur if the product were only put in the circuit while a reactive load (such as a motor) were running, and taken out of the circuit when the motor is not running. This is impractical, given that there are several motors in a typical home that can come on at any time (refrigerator, air conditioner, HVAC blower, vacuum cleaner, etc.), but the unit itself is intended for permanent, unattended connection near the house breaker panel.

For commercial facilities, power factor correction will rarely be cost-effective based on energy savings alone. The bulk of cost savings power factor correction can offer is in the form of avoided utility charges for low power factor. Energy savings are usually below 1% and always below 3% of load, the higher percentage occurring where motors are a large fraction of the overall load of a facility. Energy savings alone do not make an installation cost effective.

End of Quote