Until relatively recently a lot of the houses in this city would have had dry lavatories, not connected to the town sewage. The one in our old house seemed to have moved three times, most recently from the North East to the South East corner. Where they had running water, they were squatters and I imagine for the first half of the twentieth century, sit-down toilets were about as common as thrones, and no doubt considered with the same admiration. In fact around a hundred years ago a sit-down toilet was installed in a nearby town in anticipation of a visit by the Meiji Emperor.
From the second half of the twentieth century there has been a dramatic movement from squatters to sitters, and the toilet seat has burst into Japanese culture. Japanese toilet seat design lacks the wondrous assortment of colours, materials and patterns available in the UK market, but makes up for it with the availability of gadgets. Many houses may not have running hot water, but their toilet seats do. They are on display and available in electric shops, since toilet seats seem to be more electrical devices than plumbing.
The first attraction for the consumer is perhaps warmth. Most houses are not centrally heated, and buildings are often assembled in a modular way, rather than rooms being fit into the thermal envelope of a house. The lavatory itself has not completely been accepted as a room in the house anyway, as evidenced by the toilet slipper. This humble piece of footwear will surprise the visitor to Japan and often embarrass him as he walks back into the rest of the house with "toilet" written on each foot. I believe the toilet slippers are there because the toilet remains conceptually "outside" in the complex world of uchi to soto (inside and outside) that informs a lot of Japanese culture but very little of its thermal efficacy. When it is freezing outside, it is freezing in many lavatories.
The result is that the seats can get pretty cold. With a squatter this is not an issue, since there is no seat and no contact, and not so much heat is lost through convection or radiation, but electrical heating elements can soften the thermal shock of conducting heat away from the fleshy behind. Since these heating elements are electrical, these devices must also be very attractive for electricity companies, as they put several hundred yen on each month's electricity bill for each house. Now they are advertising low-energy seats, but they still use substantially more than a seat with no plug on it.
The hi-tech toilet seat that we have has a low-energy function, which makes a light come on saying "low energy". It has a "super low energy" function too. This makes the light flash.
There are also elaborate washing and bidet functions with hot and cold running water, elevating the humble toilet seat further and further above a hole in the floor. These are not considered particularly luxurious and you can find such toilets in shops and restaurants and even some public conveniences.
Of course the seat heater in our house is switched off, but if we ever need it I suspect it would do a good job heating the whole room.
