roof tiles leaning at a wall during renovation for german gebaeudeenergiegesetz geg, meaning building energy law

gebaeudeenergiegesetz german geg building energy law roof tiles old wall house isolation efficiency renovation renewable power government heating system refurbishment costs climate change environment act residential real estate property heat finance gas pump investment oil conversion regulation ecology economic saving duty environmental stream paragraph homeowner text germany architecture leaning against during for meaning that prescribes efficient insulation