I got this last week as a late Christmas present and so far it seems pretty cool.
Insallation is allegedly very easy, and probably is for most people. The device is basically two parts. This first part is the monitor that mounts on the outside of your electric or electronic meter (though check the Black and Decker website to make sure yours is compatible). Mine was supposed to be compatible but the spinning disk on my particular meter didn’t quite line up as nicely as advertised with the sensor arm and took a bit of very frustrating adjusting before it was able to correctly take measurements. I’ll bet later versions mount the arm on an adjustable swivel to make installing easier instead of currently having to adjust the entire unit, mounting bracket and all.
The second part is also very easy. With a bit of middle school math you plug (no pun intended) your electric rates into the base unit and then you are set to go. (The instructions are fairly easy to follow on this part but be sure to read the troubleshooting sections where they hid how to re-syncronize the base with the meter monitor.)
The monitor keeps track of your energy usage in kilowatt hours and in dollars and will estimate your monthly useage (provided you give it an accurate sample). The most useful thing about the monitor is the ‘tare’ function that allows you to isolate the energy usage from a particular appliance even your air conditioner, something other power monitors are unable to do. It also has a tempurature and time display that can be handy.
Although you will probably have to put some effort into cutting your energy useage to justify the $100 price tag, a teenager or two might make it very worthwhile.
A couple of other handy reviews: