Tailored domestic retrofit decision making towards integrated performance targets in Tianjin, China

Due to global warming and energy exhaustion, building retrofitting has attracted increasing attention worldwide. With 67.1 billion square meters of existing building area, China normally targets separate defect remedies to improve building energy efficiency in conventional renovation practices rather than taking a holistic approach to optimize whole building performance. This article presents a working procedure that is employed in the decision-making process of domestic retrofits in China from an architect’s perspective, combining building-sculpt redesign with the overall performance targets. This study examines three representative residences of different ages and dimensions as case studies to demonstrate a simulation-based holistic approach of integrating form, fabric and system strategies to improve environmental performance and reduce house-hold energy consumption without compromising building aesthetics in retrofit design. Different retrofit routes and corresponding priorities should be applied towards different conditions for different purposes. The simulation results indicate that within the service life, the older the residence, the greater the retrofit potential. For the 1981 residence, a holistic approach could achieve an energy savings of 78.1% and a CO2 savings of 92.6%. For the 1995 case, the holistic approach could reduce energy consumption by 66.6% and CO2 emissions by 76.6%. When designed properly, a 36.9% reduction in energy consumption and a 44.6% reduction in CO2 emissions could be achieved for the 2002 residence.