The unit installs easily. I think it took me about 5 minutes to get it up and running. It requires 4 AA batteries (not included). I was actually surprised at how easy the installation was.
The data that the unit displays is very useful for people like me who are trying to cut their expenses. The EM100B shows current usage and also estimates how much you are spending on electricity. You can use the device to identify potential energy hogs. For instance, I found that while my heat pumps were running it was costing .45 cents per minute.
I would highly recommend the Black and Decker EM100B Energy Saver Series Power Monitor to anyone who wants to spend less on electricity. This device can pay for itself in no time!