Efergy Elite
The Efergy Elite is a home energy monitor that uses circuit transformers (CT's) in the home's electrical panel to measure current entering your home. The current transformers plug into a transmitter that transmits (up to 230' at 433 MHz) energy data to an energy dashboard. The homeowner selects the voltage the home uses and a simple (simple because power factor is omitted) power calculation results in the home's wattage consumption.
Installation is very simple but an electrician should be contacted for those uncomfortable working around electricity.