"M Q" wrote in message
news:Ndcph.2142$8B5.981@trnddc08...
Does anyone know whether residential power meters measure
real power or apparent power (vector sum of real and reactive power).

I have found claims for each on the web, so I am really only
interested if you can give a pointer to some authoritative
document such as a utilities commission decision, a statement
by a utility, or a spec for residential meters.

They measure real power. You can Google for "electrodynamometer power
meters."