To begin with, the houses at the time were completely different from the houses of today. They were made stone with a large wall thickness that allowed for greater protection against the freshness of the outside air. Today modern houses have no huge walls like before, because the constructions and its materials are enormously improved. The glass wool for example, which allows an excellent conservation of the inner temperature. Plus, the old houses had big fireplace to warm up. The new houses have an electrical system that allowed the Radiators'invention.