Kotatsu (Heated Table)

Overview

A kotatsu is a heated table designed to warm a small family group sitting underneath a thick quilted blanket. The Table Frame supports a wooden Table Top, under which an electric Heater Assembly radiates warmth. A Temperature Controller regulates temperature, and the Futon Blanket draped over the tabletop traps the heated air, creating a warm nest even in an unheated room.

The design originated in medieval Japan but modernized in the 1950s with electric heating. Unlike room heating, a kotatsu concentrates warmth only where people are sitting, reducing overall energy use while maximizing comfort in winter. It serves as both furniture and a social gathering point.

How it works

The Heater Assembly is mounted underneath the tabletop on a Heater Mounting Bracket, where a Heating Element radiant coil glows orange-red when powered. A Safety Guard Cage prevents accidental contact. The Temperature Controller senses ambient temperature and cycles the heater on and off through a Relay, maintaining the set point on the Temperature Dial.

People sit around the table with the Futon Blanket draped over their laps and the tabletop. The blanket weight and the enclosed air pocket create an insulating cocoon, the heater runs at modest wattage because very little heat escapes. A Thermal Fuse in the heater cuts power if temperature ever exceeds a safe limit.

The Electrical Harness runs from a standard wall outlet through a Mains Power Cable to a Power Switch, then to the Terminal Box where connections feed the heater and thermostat control circuit. The entire electrical path is designed for safety: the cord has a grounded plug, the switch includes a thermal breaker, and a short cord keeps the connection away from foot traffic.

The Futon Mounting System system of Blanket Clip fasteners holds the blanket in place so it does not slip off during the evening. The blanket itself is constructed from Outer Fabric outer covering, Insulation Layer insulation, and Inner Backing inner lining, all quilted together.