We are comparing single-phase and three-phase induction motors, of course, not brush motors.
Once running, the operating efficiency between the two types of ind. motor is of little actual significance to a home user, as you can't 'save on wire' if you use a single phase + a neutral at the point of use, and how many domestic three-phase food blenders, wash machines, hair driers, dish-washers, 'fridges etc. are on the market?
The question was '3ph for domestic use' and all in all I still can't see any valid reason for it. If you want to save a few $$$s on a bit of wire, buy 230v kit and have done with it.
Actually, I'd bet that dc-inverter brushless motors [no commutator; a permanent magnet armature; a chip and solid state switching to the field windings ] will sweep all these 'ancient' motors away in the next few years, for their starting torque, efficiency, small size and variable speed qualities.
Alan
