One of the main culprits of electrical energy loss is voltage and current is being consumed out of phase. This is caused by inductive loads such as refrigerators, air conditioners, fans etc.Second would be loss due to heat caused by a totally resistive device or overloading the wire size in the branch circuit. Caused by electric heaters, filament light bulbs and having too much load on one circuit.
Now....What if you could invent a computerized main circuit panel. That detects and corrects out of phase power use. Through small view screen you can not only see your power efficiency but it could tell you what circuits are loosing electricity through heat loss because of over loading. There are some cases where defective appliances zap a lot of energy because of shorts in their coil windings. They can be detected on start up because these appliances cause a power drop on start up. That is why if you ever been in a house with a defective frig, the lights flicker when it starts up. To confirm this you only have to wait for about 15 minutes then put your hand on the compressor. It will feel hot to the touch.