Build you own Smart Electricity Monitor using the Arduino Yun or the Particle Photon.
A nice feature of the project is that the monitoring is flexible and it’s completely wireless (except for the Current Transformer of course), allowing continuous monitoring from a PC or phone and permanent storage on the Cloud.
Measured accuracy was 6% (typical), which is excellent for such a simple circuit. Even better accuracy was observed after calibration.
http://www.akellyirl.com/electricity-meter-using-anarduino-or-particle-photon/
