Since we don't have central heating to warm our cold toes in the winter, we rely on the heated pad under our rug in the living room. Despite the chilly tiled flooring, this surprisingly warms not just your feet, but the rest of you as well. (Sitting on the floor can feel warmer than sitting on the couch.)
We also use a portable kerosene heater, even though they can be smelly, the living-dining-kitchen room gets surprisingly cozy (we're talking a high of 65 F). Granted you will often find us bundled up in several layers (including my new silk long johns) and toting a hot water bottle (winter life's best kept secret!!). Unfortunately Japanese houses are not made very well, so the outside air seaps right in. And Tokyo houses don't have the big kerosene heaters (with a vented pipe outside) that Hokkaido has; so even though it is colder up there outside, it can feel colder down here inside.
