Reduce electricity bill by 20%

lol@wxmlad - your post reminded me of something I read in the Telegraph at the weekend that also made me laugh.

The Energy Saving Trust are running an advertising campaign that advises turning the thermostat down by 1 degree can cut 10% off the cost of a heating bill. One columnist jokingly commented that turning it down by 10 degrees would result in a bill of £0 and turning it down by 11 or more would mean the gas company would have to start paying him.

I found it amusing anyway....

I wouldn't go quite so far to call these devices a scam - but !

Things like these have been around for some years mainly advertised for things like fridges and freezers. There is some degree of engineering truth in their claims, by altering the power factor of an electric unit it is possible to use less electrical energy to drive that unit. However what degree of savings would be achieved are very debateable, as I said, most likely to be on motor driven things. The biggest users of power in a house are not motor driven ie: cooker, kettle, toaster and heating elements in washing machines etc.
I have put a simple explanation of Power Factor below !

Power factor

The power factor is dependent upon the characteristics of the electrical appliances connected and the relationship between the the amount of real and reactive power which is absorbed.

In the power triangle diagram, cos(theta) is the power factor and it indicates the relative size of the reactive power component measured in Volt-Amperes-Reactive (VAR).

When the impedance of the circuit is purely resistive, there is no reactive component and the apparent power is equivalent to the real power (i.e. cos(theta)=0). When reactive components are introduced (inductance or capacitance) the impedance becomes a complex quantity with a resistive and a reactive component:

* impedance Z=R+jX

The reactive power component normally results from inductance present in the circuit. The inductor is a fundamental component of electrical networks and, in practice, inductance is unavoidable in standard equipment such as transformers, motors, and even cables. Inductance can be conceived as a circuit component which acts to oppose any change in the current flowing through it. The power triangle also reflects this phenomenon because the power factor angle, theta, represents the amount by which the current lags the voltage in an inductive circuit.

Therefore electrical circuits operate at a non-ideal (<1.0) power factor and one which is termed lagging (due to inductance). There is therefore a reactive power component which, whilst being the mathematically termed "imaginary" component, causes increased current flow and heating effects in wires and appliances (e.g. pump/fan motors).

The reduction of the reactive power component is desirable on technical and energy-efficiency grounds. Furthermore the electricity supply utility tariff structure penalises the reactive component of electrical load.