eil wrote:Tweet-a-watt does monitor power on the mains. Unless you're talking about the feed line that comes into a house? If so, I'd be keen to hear about suggestions for this as well. I'd LOVE a tweet-a-watt-like device that can measure all of the current being consumed by everything in the house.
Ah, sorry, didn't make myself clear, I would be monitoring normal mains banned too. It's really just an interesting idea/project. I have already built a USB controllable mains strip with six individually switched outlets, and thought it might be interesting to add energy consumption monitoring too.
As for whole house stuff, I don't really know much about it to be honest, but I did see a web site where someone simply used a clamp meter on one line. That's what made me think of doing it this way - cheap clamp meters measure AC by simply giving an RMS readout based on a 50/60Hz sine wave.