Denise, 58, never dreamed of owning her own home. But her mother convinced her to build a semi-detached house in Berlin about 25 years ago. The children are now grown up and the gas heating is outdated. How does a house become sustainable?
Denise, 58, never dreamed of owning her own home. But her mother convinced her to build a semi-detached house in Berlin about 25 years ago. The children are now grown up and the gas heating is outdated. How does a house become sustainable?