Apparently, passive house design has become quite popular in Germany. What’s a passive house, you say? It’s basically a house that uses a variety of methods to achieve very low energy usage. Common techniques that are often used in passive homes include having windows facing the sun, superinsulation, and airtight construction. WeberHaus is a German company that has built over 29,000 prefab homes since they were founded in 1960, pictured below is their Passive House model which can use up to 90% less energy than a conventional house. Gotta love that German obsession with efficiency!