The average temperature in Stockholm in January is -3°C (27°F). For Marie Granmar and Charles Sacilotto it can be much warmer thanks to the greenhouse that blankets their home. “For example at the end of January it can be -2°C outside and it can be 15 to 20°C upstairs,” explains Sacilotto. He was inspired to build a house-in-a-greenhouse through his relationship with architect Bengt Warne who began designing the first Naturhus (Nature House) in 1974*.