Your Walls Are Cooking You Alive — Japan Fixed This 200 Years Ago For $50

If you go back four hundred years, earthen plaster walls were the standard construction in virtually every traditional Japanese home — from Kyoto's densest merchant districts to the most remote farmhouses across the archipelago. But today, in Kyoto alone, six thousand of those structures were demolished in a single eight-year period. They are called tsuchikabe — or earthen plaster walls. And they have been documented by researchers at a Japanese university to cut peak summer indoor temperature swings in half compared to a modern lightweight-frame house — without electricity, without synthetic materials of any kind. But if they worked so well, why did we stop building them? Let's find out.