Japanese bath areas are 99% of the time separate from toilets. And the Toto models don't require a hot water line. Yet its pretty common to have heated jet functions. These models allow these features. Its more to do with economics of widespread availability.
The ones I have used in the last few years all have a small instant warmer unit. Japanese homes don't always have access to hot water tank & even the shower space is serviced by a electronically activated gas heater.
Source: I live here in JP, and my parent company's main revenue stream is from gas heaters OEM, heating appliances and even bespoke plumbing & installations.
The ones I have used in the last few years all have a small instant warmer unit. Japanese homes don't always have access to hot water tank & even the shower space is serviced by a electronically activated gas heater.
Source: I live here in JP, and my parent company's main revenue stream is from gas heaters OEM, heating appliances and even bespoke plumbing & installations.