I use the Currentcost EnviR. It costs $129 to install, has an independent wireless transmitter to a meter that you can place anywhere in your house. There are several different websites that can receive the data and maintain graphs of usage. Some are subscription, but meniscus.co.uk is free.
Google whole home energy monitor and you will find lots of choices. I picked the EnviR based on features and cost.
(I'm guessing the customer is looking at this for a consumers point of view.)