こたつ kotatsu: a low table with an electric heater and a futon 布団 (blanket, cover)
For most people, winter (fuyu 冬) in Okinawa is mild. For me and my puppy, it is harsh and cold. So the first winter on island, I bought a kotatsu. It is really economical (keeps down whole house heating costs) and is really comfortable. Some mornings I never want to leave it; I just want to stay and drink my coffee under the warmth.
I purchased it at Nitori ニトリ (a cheap chain home goods store) for a really low price, as well as a set of matching futon, pillow, and floor mat. During warmer months, the futon blanket and heater is removed, leaving just regular table. I have a different cover for the floor mat during spring through fall that I use.
My little dog also loves snuggling under it with me. Maybe for people tolerant of cold weather, this type of thing is not needed in Okinawa, but for this island girl it is a necessity.