Aircon heating

For Osaka residents with not so well-insulated houses, which of the remedies below did you find is enough to warm you during winter?

  1. Kotatsu

  2. Electric Blanket

  3. Portable Heater

  4. Airconditioners

  5. Combination?

For airconditioners, who else opted for window airconditioners instead of split type? May I ask how was your experience?