Panasonic has introduced electric radiant rugs into the Japanese market. Normally we would say this is just another electricity waster, but we used to have prototypes for a heated carpet that never went into production, and until we gave them up after the rubber backing started drying out they were absolutely wonderful; even if the house was at 55 degrees one could sit on that rug and feel warm as toast. The kids and the cat were glued to it. A 2 tatami mat sized rug is rated at 500 watts, but heats up to 114 degrees, which is way more than you need for comfort. Our old one drew 200 watts and was more than enough.
Why heat the whole house when toasty feet are all you need? Panasonic, bring those rugs to North America. ::Freshome