Thin House, Japan

In northern Japan, yukadanbō (床暖房) (literally, floor heater) is a type of radiating heater beneath the floor in some rooms of newer houses, where heated fluids are circulated to provide warmth. The cost is expensive, so sometimes this type of heater is only installed in small rooms like the "clothes changing room". Electric carpets have become popular in recent years.
Finally, a traditional type of heater known as a kotatsu is also still widely used today. The kotatsu can come in multiple forms, but the more common is as an electric heating element attached to the underside of a low table: the table is typically surrounded by a light duvet-like cloth to keep the heat in. This type of table is common in the washitsu.
• Electricity
Japanese dwellings connected to the nation's power grid have 100 V AC electricity at outlets throughout the home. The line frequency is 50 Hz in eastern Japan, and 60 Hz in the western part of the country. Service of 30 or 50 A is typical. Many domestic appliances operate properly at either frequency. Outlets resemble those formerly used in the United States, with two vertical slots. The slots are usually of equal width and many sockets lack earthing capability. Outlets in the kitchen, toilet, and bathroom, as well as those supplied by the ceiling for air-conditioning units do usually have earthing, either in the form of an extra round hole or a covered binding post. Devices designed for use with water, such as clothes washers and heated toilet seats, often have a separate earth wire or earth pin. Adapters are readily available to convert such plugs and so allow their use in all types of sockets.