If you want to save on your monthly electric bill and reduce your greenhouse gas emissions at the same time, you might buy a new energy-efficient refrigerator. Or water heater. Or clothes dryer. But if you can only replace one of these, which will give you the biggest payback?
You could try to figure that out by comparing the energy-use labels from your existing appliances with those of the models you might purchase if you still have your old labels. Even then, the numbers may differ significantly from your actual usage, depending on factors such as age, condition, and your local climate. But soon, there could be a much easier way to figure out exactly how much power is being used by every appliance, lighting fixture, and device in your home, with pinpoint accuracy and at low cost, thanks to devices and software developed by researchers at MIT.
The team's findings, developed over several years of intensive research, are described in a series of papers, including one published in the IEEE Sensors Journal, by MIT Professor of Electrical Engineering Steven Leeb and recent graduates David Lawrence, MEng '16, and John Donnal, Ph.D. '16.
While many groups have worked on developing devices to monitor electricity use, the new MIT system has some key advantages over other approaches. First, it involves no complex installation: No wires need to be disconnected, and the placement of the postage-stamp-sized sensors over the incoming power line does not require any particular precision; the system is designed to be self-calibrating.
Second, because it samples data very quickly, the sensors can pick up enough detailed information about spikes and patterns in the voltage and current so the system can, thanks to dedicated software, tell the difference between every different kind of light, motor, and other device in the home and show exactly which ones go on and off, at what times.