Search

Premium Membership

Get 15% OFF on Pro Premium Plan with discount code: UX21M. Study specialized electrical engineering articles and papers in Low- and High-Voltage areas.

Home / Technical Articles / The real truth behind household power savers
Household Power Saver
Household Power Saver - Efficent? What is the real truth?

A household power low voltage saving devices has recently received a lot of attention from both consumers and manufacturers. It is generally used in residential homes to save energy and to reduce electricity bills. It is a small device which is to be plugged in any of the AC sockets in the house (Mostly near Energy Meter). Moreover, some of the companies claim that their power savers save up to 40% of the energy.

Many people believe that the claims made by the power savers manufacturing companies are false. Almost all people who buy power savers do it to reduce their electricity bills.

Many people who have used these power savers said that they could reduce their electricity bills with the devices; however the reduction was not as much as they had expected. Moreover, they could not figure out if the reduction in electricity bills was due to the power savers or because of their efforts to reduce their electrical usage. There have been several serious discussions about the genuineness of the device.

In this note, we will try to find the real truth behind these power savers which claim to save as much as 40% of energy.

Working Principle of Power Saver as per Manufacture

A Power Saver is a device which plugs in to power socket. Apparently just by keeping the device connected it will immediately reduce your power consumption. Typical claims are savings between 25% and 40%.

It is known that the electricity that comes to our homes is not stable in nature. There are many fluctuations, raise and falls, and surges/Spikes in this current. This unstable current cannot be used by any of the household appliances. Moreover, the fluctuating current wastes the electric current from the circuit by converting electrical energy into heat energy.

This heat energy not only gets wasted to the atmosphere, but also harms the appliances and wiring circuit.

Household power saver device - Schematic diagram
Household power saver device - Schematic diagram

Power Saver stores the electricity inside of it using a system of capacitors and they release it in a smoother way to normal without the spikes. The systems also automatically remove carbon from the circuit which also encourages a smoother electrical flow. This means that we will have less power spikes. More of the electricity flowing around circuit can be used to power appliances than before.


Basically it is claimed that Power savers work on the principle of surge protection technology. Power savers work on straightening this unstable electric current to provide a smooth and constant output. The fluctuation in voltage is unpredictable and cannot be controlled. However, the power savers utilize current fluctuation to provide a usable power by acting like a filter and allowing only smooth current to pass through the circuit. Power savers use capacitors for this purpose. When there is a surge of current in the circuit, the capacitor of the power saver stores the excess current and releases it when there is a sudden drop. Thus only smooth output current comes out of the device.

Moreover, a power saver also removes any type of carbon in the system, which facilitates further smoother flow. The main advantage of power savers is not that they provide a backup system in times of low current, but that it protects the household appliances. It is known that a sudden rise in the power can destroy the electrical appliance. Thus, the power saver not only protects the appliance but also increases its life. Moreover, they also reduce the energy consumption and thus the electricity bills.

The amount of power saved by a power saver depends on the number of appliances on the electrical circuit. Also, the system takes at least a week to adapt itself fully to the circuit, before it starts showing its peak performance. The maximum amount of voltage savings will be seen in areas where in the current fluctuation is the highest.

Household Power Saver Scam Review

Power Factor Correction for residential customers (home owners) is a scam? At most, each unit is worth as an investment. Power factor correction does make sense for some commercial / industrial customers.

Many companies are promoting and advertise that their Power Saver unit are able to save domestic residential power consumption by employing an “active power factor correction” method on the supply line. The concept seems pretty impressive as the concept is true and legally accepted. But practically, we will find that it’s not feasible.

To support above statement first we need to understand three terms:

  1. Type of electrical load of house,
  2. Basic power terminology (KW, KVA, KVAR).
  3. Electrical tariff method of electricity company for household consumer and industrial consumer.

There are basically two kinds of load that exists in every house: one that is resistive like incandescent lamps, heaters etc. and the other that’s capacitive or inductive like ACs, refrigerators, computers, etc.

The power factor of a Resistive Load like toaster or ordinary incandescent light bulb is 1 (one). Devices with coils or capacitors (like pumps, fans and florescent light bulb ballasts)-Reactive Load have power factors less than one. When the power factor is less than 1, the current and voltage are out of phase. This is due to energy being stored and released into inductors (motor coil) or capacitors on every AC cycle (usually 50 or 60 times per second).

There are three terms need to be understand when dealing with alternating (AC) power.

  1. First Term is kilowatt (kW) and it represents Real power. Real power can perform work. Utility meters on the side of House measure this quantity (Real Power) and Power Company charge for it.
  2. The second term is reactive power, measured in KVAR. Unlike kW, it cannot perform work. Residential customers do not pay for KVAR, and utility meters on houses do not record it too.
  3. The third term is apparent power, referred to as KVA. By use of multi meters we can measure current and voltage and then multiply the readings together we get apparent power in VA.
Power triangle
Power triangle

Power Factor = Real Power (Watts) / Apparent Power (VA)

Therefore, Real Power (Watts) = Apparent Power × PF = Voltage × Ampere × PF.

Ideally a PF = 1, or unity, for an appliance defines a clean and a desired power consumption mostly Household Equipments (The dissipated output power becomes equal to the applied input power).

In the above formula we can see that if PF is less than 1, the amperes (current consumption) of the appliances increase, and vice verse.

With AC Resistive Load, the voltage is always in phase with the current and constitutes an ideal power factor equal to 1. However, with inductive or capacitive loads, the current waveform lags behind the voltage waveform and is not in tandem. This happens due to the inherent properties of these devices to store and release energy with the changing AC waveform, and this causes an overall distorted wave form, lowering the net PF of the appliance.

Manufacture claim that the above problem may be solved by installing a well-calculated inductor/capacitor network and switching it automatically and appropriately to correct these fluctuations. A power saver unit is designed exactly for this purpose. This correction is able to bring the level of PF very close to unity, thus improving the apparent power to a great extent. An improved apparent power would mean less CURRENT consumption by all the domestic appliances.

So far everything looks fine, but what’s the use of the above correction?

The Utility Bill Which We pay is never based on Apparent Power (KVA) but it is based on Real Power (KW). The utility bill that we pay is never for the Apparent Power- it’s for the Real Power.

By Reducing Current Consumption Does Not Reduce Power Bills of Household Consumer.


Study of Power Saver in Domestic Load

Let us try to study Household’s Reactive-Resistive Electrical Load and Voltage Spike Characteristic by example.

1. Power Saver in Reactive Load of Home

Let’s take One Example for reactive Load: A refrigerator having a rated Real Power of 100 watts at 220 V AC has a PF = 0.6. So Power=Volt X Ampere X P.F becomes 100 = 220 × A × 0.6 Therefore, A = 0.75 Ampere

Now suppose after Installing Power Saver if the PF is brought to about 0.9, the above result will now show as: 100 = 220 × A × 0.9 And A = 0.5 Ampere

In the second expression we clearly show that a reduction in current consumption by the refrigerator, but interestingly in both the above cases, the Real Power remains the same, i.e. the refrigerator continues to consume 100 watts, and therefore the utility bill remains the same. This simply proves that although the PF correction done by an energy saver may decrease the Amperage of the appliances, it can never bring down their power consumption and the electric Bill amount.

Reactive power is not a problem for a Reactive Load of Home appliances like A.C, Freeze, motor for its operation. It is a problem for the electric utility company when they charge for KW only. If two customers both use the same amount of real energy but one has a power factor of 0.5, then that customer also draws double the current. This increased current requires the Power Company to use larger transformers, wiring and related equipment.

To recover these costs Power Company charged a Penalty to industrial customers for their Low power factors and give them benefits if they improve their Power Factor in. Residential customers (homes) are never charged extra for their reactive Power.

2. Power Saver in Resistive Load of Home

Since a resistive load does not carry a PF so there is not any issue regarding filtering of Voltage and Current, So Power = Voltage X Current.


3. In Voltage Spike / Fluctuation condition of Household Appliances

In above discussion simply proves that as long as the voltage and the current are constant, the consumed power will also be constant. However, if there’s any rise in the input voltage because of a fluctuation, then as explained above your appliances will be forced to consume a proportionate amount of power. This becomes more apparent because current, being a function of voltage, also rises proportionately. However, this rise in the power consumption will be negligibly small; the following simple math will prove this.

Consider a bulb consuming 100 watts of power at 220 volts. This simply means at 240 volts it will use up about 109 watts of power. The rise is just of around 9% and since such fluctuations are pretty seldom, this value may be furthermore reduced to less than 1%, and that is negligible.

Thus the above discussions convincingly prove that energy savers can never work and the concept is not practically feasible.


What happens when Power Saver is installed?

The Fig shows the result of using Power Saver. The air conditioner (which has a large compressor motor) is still consuming reactive power but it is being supplied by a nearby capacitor (which is what is in those “KVAR” boxes). If you were to mount it at the air conditioner and switch it on with the air conditioner plus you sized the capacitor perfectly, then there would be no reactive power on the line going back to the fuse panel.

If the wire between your fuse panels is very long and undersized, reducing the current would result in it running cooler and having a higher voltage at the air conditioner. These savings due to cooler wiring is minimal.

What happens when Power Saver is installed
What happens when Power Saver is installed

A further complication is that if you install the “KVAR” unit at the fuse panel, it does nothing for the heat losses except for the two feet of huge wire between the fuse panel and the utility meter. Many KVAR units are marketed as boxes that you install at a single location.

If your power factor box is too large, then it will be providing reactive power for something else, perhaps your neighbor.

Conclusion

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.

Second, the only potential for real power savings would occur if the product were only put near 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 Power Saver itself is intended for permanent, unattended connection near the house breaker panel.

And certainly not in the way the manufacturers recommend that they be installed, that is, permanently connecting them at the main panel. Doing that drags the power factor capacitive when the inductive motors are off and could create some real problems with ringing voltages.

The KVAR needs to be sized perfectly to balance the inductive loads. Since our motors cycle on and off and we don’t use the air conditioner in the winter, there is no way to get it sized properly unless we have something to monitor the line and switch it on and off capacity (capacitors) as necessary.

Adding a capacitor can increase the line voltage to dangerous levels because it interacts with the incoming power transmission lines. Adding a capacitor to a line that has harmonic frequencies (created by some electronic equipment) on it can result in unwanted resonance and high currents.

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.

Premium Membership

Get access to premium HV/MV/LV technical articles, electrical engineering guides, research studies and much more! It helps you to shape up your technical skills in your everyday life as an electrical engineer.
More Information
author-pic

Jignesh Parmar

Jignesh Parmar has completed M.Tech (Power System Control), B.E (Electrical). He is member of Institution of Engineers (MIE), India. He has more than 13 years experience in transmission & distribution-energy theft detection and maintenance electrical projects.

193 Comments


  1. Reuben
    Apr 08, 2021

    First time I’ve heard of carbon being in electrical circuits lol

    I’ve certainly missed this being an electrical engineer for 30 years. Guys, your article is rendered ridiculous when you write things like this.


    • Frank
      Apr 15, 2021

      They don’t even give instructions on what to do with the huge pile of carbon the devices remove, I’m wondering if I could get a truck big enough to ship it. Do you think the power utility would take it off my hands?


  2. Joshua Billing
    Apr 08, 2021

    Yeah, as soon as I read that it corrected Sine waves with capacitor technology, (and that is paraphrasing by taking the vague descriptions of what they claim the device does to save you money, put them all together, filtering out the nonsense and crap, and reduce the claims down to the lowest common denominator) and you are left with a magic box that SOMEHOW filters power from just one outlet near your supply meter, and corrects ALL of the power in your house even though all of the appliances, lights, outlets and etc aren’t all on one breaker? It’s a freakin miracle!! They should call it the Jesus Gigawatt Box!! So they basically think we are dumb enough to believe that all of the electricity in our house will filter through this box at some point in the circuit, or that the electricity is just radiating everywhere around us, and like a giant ghost trap( ala Ghostbusters) this device pulls in the energy all around us that is being emitted through our walls from electrical wires? It will also cut down on the radiation emitted from said wires? Wow… I had no idea that governments around the world were pumping in such dangerous radiation and stealing money from us, and the hair on our heads doesn’t even stand up or we don’t build up electrical charges simply by moving through the charged particles that are coursing thru our homes in great enough amounts to shoot electric fireballs at one another.. Seriously, if 30% of our power bills was just wasted electricity, lost inside our homes and residual dirty carbons coming thru our electrical wiring, the crisis these power companies would be concerned with wouldn’t be the money they could potentially lose, it would probably be the millions they would potentially kill because of their product, and the trillions in property damage caused each year… I know my science isn’t even remotely close to accurate, I’m merely explaining all of the crazy thoughts in my head watching the infomercial for one of these products.. I am just amazed that claims like this could be made, and products that are so clearly BS, and evident scams can be freely marketed, even when every scientist with a basic understanding of the principles of electricity is screaming scam at their TV’s in millions of homes in the USA.. Why do we have so many types of crime investigation bureaus for every other kind of crime, but no agency looking into Snake oil salesmen? It makes about as much sense as the science that makes this product sell


  3. John McHugh
    Apr 07, 2021

    The Voltex device adds claim that the device is patented so I asked for the patent numbers, reminding them that falsely claiming a patent where none exists is a crime. The reply:
    “Patent is very complex thing so in order to be able to sell in multiple places the company decided to risk it for the expansion. We assure you that all of the item we sell is secured and made with high valued materials.” This appears to be a power factor correction device, at best, and will probably not alter your electric bill unless your power company has very strange metering.


  4. Malcolm Metcalfe P.Eng.
    Apr 04, 2021

    It is very hard to believe that this was written by an engineer. For example – the calculations on the refrigerator are wrong. The current is not calculated correctly – AND while correcting power factor reduces reactive power (kVARs) it does NOTHING to the WATTs consumed. Residential customers almost everywhere in North America do NOT pay for amps, VARs or kVA – only for watt-hours. The ONLY change to a bill would be the result of a small loss in the house wiring caused by reducing current – but that would almost certainly be less than 5% unless the power factor was far less than 70%.


  5. Dan
    Apr 01, 2021

    I almost agree with you 100%, but don’t forget about losses. Although your electric bill won’t see any noticeable change, there is additional energy lost (heat) from the spikes and waveform distortion. This is due to the fact that most circuits are designed to pass low frequency waveforms and filter the higher frequencies and spikes caused by various inductive devices. As an example, if you have a good quality power strip, you may notice that it gets a little warm. That is the filtering built into the power strip. For those of you that are yelling scam, the part you are misunderstanding about this article is the operational power saver device which when applied correctly works very well but has no impact on your home utility bill. What the article is trying to tell you is that even if you get a working device, it won’t change your utility bill because you are billed on ACTUAL power used which will be the same regardless of whether or not you have PF correction. PF devices are primarily used in manufacturing facilities and are charged for peak current which is a completely different ballgame and unrelated to residential utility bills.


  6. Brenda
    Mar 23, 2021

    I’m a senior trying to cut hydro costs. This sounded good to me, so I googled it to get info. Thanks so much for providing the things I needed to know. I’ll admit I don’t understand all of your article, but enough to realize it’s not worth paying out my hard earned money for this item. Thanks so much.


  7. MICHAEL MILLER si
    Mar 22, 2021

    I sincerely appreciate being able to learn the truth about any product I might like to purchase. Thank you


  8. John
    Mar 20, 2021

    This has always sounded like a SURGE Protector. My area, Florida, the power co. (LCEC) has installed Surge suppression at the entry point to the house. That would be the same effect (?). This offers a guarantee of protection against surges. We get lots of bad storms for 5-6 months, some are Tropical / Hurricane. 20+ years with no problems. To me that is the benefit. Placing another device should not be helpful. Please correct me if I am not correct.


  9. Joanna Hulsman
    Mar 15, 2021

    I purchased the ROHS Electricity Saving Spike ((misspelled Spixe) Buster to save on my electricity bills. DON’T WASTE YOUR HARD-EARNED MONEY! This is the most bogus product I’ve ever seen, a scam just like any other to part you from your money. It never saved a cent on my electricity bills, and the front two green lights went out on one of the two units less than a month after installing. I’d like to sue the company(ies) responsible for this ripoff.


  10. Lindy
    Mar 11, 2021

    Thank you so much, you just saved me $50. Bless you.


  11. Karl Schneider
    Mar 07, 2021

    All of these ‘review’ sites are nothing more than poorly disguised ADVERTISEMENTS for these useless scamming pieces of Chinese crap that can NOT do what they lie about….er, ‘claim’. Anybody dumb enough to pay for one of these bogus contraptions deserves to be swindled.


    • Karen Kapfhammer
      Mar 08, 2021

      These devices are like putting a water filter on one faucet and expecting it to benefit the whole house. A surge protector gets put in line first, and is a good way to protect appliances and electronics. This article is such a scam


    • Joshua Billing
      Apr 08, 2021

      Seriously. If a little voice in your head wasn’t screaming “don’t buy this piece of $h1t, it’s a SCAM!! SCAM…SCAM.., then how would you like to invest money in ACN Telecommunication?? A great company that will be the #1 communications company when phones switch from analog to digital!! (Don’t mind the company’s 100 other aliases, or tens of thousands of complaints to the Better Business Bureau because Donald Tump himself is the key spokesman!!!) Or, how about I sell you 30k in Iraqi Dinar since the banks are going to remunerate now that democracy has taken hold, and since the banks are backed by oil the renumeration will make 1 Dinar, now valued at $.56 on the dollar, worth $36.23 per Dinar! I have approximately 56,258 Dinar that I will hesitantly part with for over a 10k LOSS because I need the money now!!! But my misfortune and lack of a sound financial plan could be a HUGE payday for YOU!! … Because if you have $31,504 (plus applicable sales tax, finance charge, national transfer rate of 10%, attorneys fees, transfer rate calculation services and insider surcharge interests, not to mention the B.S.W.S.T.D.O.H. ((brave soldier who smuggled these Dinar over here)) fees) and you have the Financial saavy to turn one man’s idea into millions, and you can wait another 6 months to reap your reward, your $31.5k (plus above fees) will make you a millionaire twice over because that measley 31.5k (plus hefty aforementioned fees*) will net you no less than the modest valuation estimate provided by my foreign currency strategists of $35.67 per Iraqi Dinar, that you wisely purchased for the embarrassingly low, and it should be illegal cause you are robbing me here, cost of $.56 each (plus signifigant, probably, definitely gray area, inside-ish, illegal aforementioned fees*) you will walk away (contract may be voided without reason or warning*) with the mindblowingly hefty sum of $2,006,722.86!! That’s a markup of, well, I’ve given you enough!! You are gonna be the freakin millionaire, you pay your own guy to do that math (10% surcharge for math calculations in this ad*… All fees due at time of contract signing✓ .Buyer accepts all money laundering and exporting charges potentially* punishable by law— Seller reserves the right to breach contract at any time– All sales final.. Charges, surcharges and fees non refundable* Buyer agrees to pay seller 15% of final sales price.. Seller not responsible for false or misleading advertising. Buyer agrees to loan his wife or daughter, whichever is the greater value, for 2 weekends a year for mostly oral and anal sex. Breach of any above conditions voids contract in which any and all monies paid for Dinar revert back to seller under the California penal code 420.69 suck it.. all sales final).. Please sign here..
      If only I could find 100 people who were dumb enough to buy one of these power saving devices.. I got a million good scams, I MEAN investments!! A million investments to get rich!! (Me not you…says the companies that make this garbage


  12. sig
    Mar 04, 2021

    big scam installed 2 in my home my bill did not go down 1 cent.


  13. Trish
    Mar 03, 2021

    You should really leave your political comments “Trump method” out of your opinion.


    • Bob
      Apr 03, 2021

      That’s right, no Trump comments, just be happy he is finally gone. Also the power saver is useless, don’t wash your money.


      • Bill
        Apr 15, 2021

        Right better save your money….gonna need more now that Biden is in charge and fuel and electrical prices have soared!

Leave a Reply to Trish

Tell us what you're thinking... we care about your opinion!

Electrical Engineering Courses

Learn to design electrical power and industrial automation systems through professional video courses.