The Hawthorne effect is a form of reactivity whereby subjects improve an aspect of their behavior being experimentally measured simply in response to the fact that they are being studied not in response to any particular experimental manipulation.
One thing we noticed here at Adafruit – once we started measuring our power usage with the Tweet-a-watt project we actually decreased power consumption – part of it was because we knew we were measuring it and each month when the power bill came we saw the bill go down.
Tweet-a-Watt is a DIY wireless power monitoring system. The project uses an ‘off the shelf’ power monitor called the Kill-a-Watt and adds wireless reporting. Each plug transmits the power usage at that outlet to a central computer receiver. The receiver can then log, graph and report the data. This pack contains nearly everything* necessary to build a single outlet monitor and receiver. To monitor additional outlets, you will need an add-on transmitter pack. One outlet can monitor up to 1500 Watts.