[red-beard]

There are watts, and then there are vars...

Motors are funny things. With inductive motors, the larger the difference between the motor speed and the system frequency (slip), the more the output. But, when measured on the meter, the power can be higher than true power.

The problem is the way power gets measured. It is a scaler vs. vector issue. The scaler says you only used X amount of power. But the vector shows you used 0.85X. Guess which one the power company charges?

When you have a bunch of inductive loads, you can add capacitors and offset the inductance. This should give you a closer to unity power factor and more correct true power usage.

The actual power is a cosine function. So, you need a pretty high inductive load for power factor correction to become an issue. The simple fix is adding a capacitor with each motor, assuming a near constant load. Most high efficient motors have capacitors, which accomplish this.

If you have old pool pump and old A/C motors, power factor correction might help. But, if you live in the north, and most of your electrical usage is a refrigerator and lights, forget it. If you have modern electrical motors, forget it. They already have capacitors to improve efficiency.

The place where PF correction actually works, is where the motor operated of a range of power output, so the capacitors needed are not constant. This is not a regular issue in houses.

So, yes, it can help. But, for most home owners, it is snake oil.