[RayVR]

The Japanese buildings are absolutely not energy efficient. They are horrible in terms of energy efficiency and durability.

Not to mention, the homes in this article represent something like 0.01% or less of actual Japanese prefab homes. Most have very few windows, which are very small. The interior spaces tend to be fairly small as well. Not these open styles.

This is all due to earthquake planning. Studies have consistently found lightweight exterior walls with lots of interior support are most likely to remain standing in a severe earthquake. The small windows reduce weight and are also more efficient since the sun in Japan will roast your house in the summer if you have big windows.