For a big house, with long DC runs, you could lose quite a bit of power, negating any savings from having a single more efficient power supply.
It's definitely tidier to have a single supply, but I'm not sure you'd see increased efficiency. You'd also need double the wiring in the buildings. Retrofitting buildings would be a nightmare.
My personal thought is that all houses should have AC and Ethernet throughout the walls. Phones can use VoIP through the ethernet, and the ethernet can be used as a DC supply via PoE. Obviously PoE would have to become more robust and ubiquitous, but it makes more sense than running dedicated DC (or phone) lines throughout a building.
For a big house, with long DC runs, you could lose quite a bit of power, negating any savings from having a single more efficient power supply.
It's definitely tidier to have a single supply, but I'm not sure you'd see increased efficiency. You'd also need double the wiring in the buildings. Retrofitting buildings would be a nightmare.
My personal thought is that all houses should have AC and Ethernet throughout the walls. Phones can use VoIP through the ethernet, and the ethernet can be used as a DC supply via PoE. Obviously PoE would have to become more robust and ubiquitous, but it makes more sense than running dedicated DC (or phone) lines throughout a building.