Significance of building performance, usability and serviceability in terms of sustainable building

Sustainable building (SB) is a comprehensive process which is able to understand user needs and requirements and create a design that fulfils these requirements while minimising environmental impacts and life cycle costs. Understanding user needs is essential in sustainable building. However, several case studies have shown that there are often significant problems in understanding the user needs and achieving the desired usability. Functional performance and social performance are becoming more and more important aspects of SB. There are several reasons for this: 1) Minimising and optimising the environmental impacts of building happens with help of comparing alternative design options. 2) Functional and social performance is an essential element of SB because that is a target of user requirements and because the user satisfaction mainly depends on functional and social performance. 3) Good functional and social performance and conformity with users' needs probably reduces the needs to make changes and rebuild. 4) The threats concerning the climate change will mean increasing requirements for building sector to diminish GHGs. This will probably mean that absolute decrease in terms of overall quantities is needed. In order to remain and improve the quality of buildings as places to work and live, focus has to be directed not only on decreasing environmental impact but also improving the functional performance of buildings and spaces. Improved consideration and management of functional and social performance is possible by developing methods for identification and understanding user needs. The premise is that especially the development of structured outlines for functional and social performance and visualisation tools would support understanding and consideration of user needs. The paper discusses the meaning of building performance and usability as aspects of sustainable building, and gives recommendations for the development of methods that support the identification and understanding of user needs.