Ah.... I don't know why the peak value of 240V RMS didn't occur to me before. It kind of makes sense, in a way.
I don't think it would be a very sensible move though. What about all the millions of appliances already in use which rely on a transformer or induction motor? That's not to mention everything which has been designed for A.C. only in the last few decades and has switches which would not last long on D.C.
It seems to me that this would just be introducing another standard for no good reason.
@Wolfgang: Voltage drop would be a big issue with 24V. I know a guy who runs his house on solar panels only, and he wired his 24V ceiling lights with 6mm2 - that's ridiculous. Besides, most small appliancess use all kinds of queer voltages inside, so they'd need a DC-DC converter like a chopper anyway. So I think a Switching mode power supply or good old transformer from 230 to whatever voltage is needed is still the better option.
