The gadget is the Kill-a-Watt Electricity Usage Monitor, by P3 International. You can find a review of the meter itself on Gadgeteer and in the customer reviews on Amazon. It looks like this:
Kill A Watt meter
Recent discussion in the thread Commercial espresso machines in the home and the older Leave it on, or turn it off?, discuss the electricity costs of using a machine on a timer or leaving it on all the time. The Kill A Watt meter would let you actually measure the electricity usage of an espresso machine and many other household appliances or electronic devices.
I was curious to see how much electricity was used on a small home machine (Silvia) going from cold to warm-up for an hour, and then sit idle... no shots were pulled in this three hour sample.
- Silvia (uninsulated boiler, PID controller, started from cold)
60 minutes - 0.12 KWH
120 minutes - 0.17 KWH
180 minutes - 0.23 KWH
The next AM, I warmed up the machine and pulled 3 shots (with some backflushing) and used 0.18 KWH in 75 minutes.