I use IoTaWatt (http://iotawatt.com/) for solar/energy monitoring at home. It works with a standard web browser (no app required) and doesn't require any kind of Internet/cloud connection (but can use one if desired). It will keep years of data internally on the SD card and you can make pretty graphs from your phone/laptop/whatever web browser, or you can download the data and do whatever you want with it. It is an open source software/open hardware design by a guy in New Hampshire. It is manufactured in the US, and it is ETL certified. ("The hardware is professionally manufactured in an ISO9001 contract facility in New Hampshire, USA. The base units are ETL safety certified to UL standards") See pics of my setup here: http://www.wlug.org/files/iotawatt/ $314.30 gets you a US 120V bundle with split-core CTs for 14 circuits (2 mains + 12 branch circuits), 9V AC reference transformer, and USB power supply. The split-core/clamp-on CTs are easy to install, just open them up, place them around the wire, and close them. If you use non-split-core CTs (not included in the bundle above), you need to to disconnect the hot lines from each circuit breaker to slip on the CT, then reattach to the breaker.