Thermal properties optimization of envelope in energy-saving renovation of existing public buildings.

Highlights: [•] The limited heat consumption per unit volume was proposed. [•] Equivalent heat transfer coefficient of external windows and wall was proposed. [•] Mathematical model on thermal insulation thickness of external wall was built. [•] Economical evaluation model was built for energy-saving renovation. [•] The economical model was verified to be feasible by an existing public building. [Copyright &y& Elsevier]