KVAR is an abbreviation for Kilo(as in 1000s) Volts Amperes-Reactive. Reactive power is basically the energy that goes into making magnetic fields in motors, charging capacitors, etc. True power, measured in Watts, is what actually does the work or gets converted into heat. Apparent Power is the vector sum of these two, and Power Factor is the ratio of true power to apparent power. Greatest efficiency occurs when this ratio is equal to 1, meaning that there is no reactive power present. Utilities and large industrial users have an interest in controlling this ratio to improve efficiency. See (link...) for more information.

When an appliance runs, you are paying for the power it uses plus the power converted to heat in the wiring the appliance uses. These gadgets have been around for years, but I have never known of anyone actually using one.

Power is not my area of expertise, but I think there's good reason to be skeptical. Utilities want to eliminate reactive loads because meters measure real power only. Loads use reactive power too that doesn't get billed. If this device works, then utilities will produce less wasted KVAs through less reactive loading and thus achieve higher efficiency, but I don't see how the customer pays less at the meter. If it's this easy to obtain a unity power factor, the utilities would be all over it for themselves.

Read this before buying.

Check out the Nest thermostat here. It's a smart thermostat that learns and wifi capable.
It's $250 but sold out. I'll be getting one as soon as it's available. I think it will be worth the investment.

Oops. here

is that your house's power factor is constantly changing based on what is running at any given moment. The correction factor that improves efficiency when the air conditioner, refrigerator and washing machine are running could cause your household voltage to be higher when those major loads are not running. This could possibly shorten the life of other electrical items in your house.

.. this product is hogwash. The "read this before buying" link is absolutely correct and based in the facts of electricity.

Best ways to save:
- Keep your HVAC air filters changed regularly
- Change to CFL and LED lights
- turn down the thermostat, throw on more covers
- check and update weatherstripping on doors
- turn off lights and appliances when not in use