People keep warm with heaters and the much loved kotatsu.
Kotatsu are low tables designed to sit on traditional tatami floors. They are covered with a thick quilt and have a heater underneath.
Kotatsu have been around since the 14th century. Traditional kotatsu use a coal pit that's built into the floor. Modern kotatsu have an electric heater that's under the tabletop.
There's something comfortable about kotatsu. Once you get used to them central heating feels boring.
Kotatsu have a social feeling to them. Families and friends sit around the kotatsu and eat meals, drink or watch television together.