Nowadays, many countries worldwide are discussing the problems of complex evaluation and certification of building structures with regard to sustainability of construction works. This is a special challenge that requires multidisciplinary and multi-criteria approach. It is long and iterative process described in mandate CEN/TC 350 that should lead into evaluation of the aspect of sustainability of construction works abreast of buildings in their lifelong cycle. It is preparing a quantitative evaluation, which should include functional properties of buildings in categorization of their environmental value, health, comfort and lifelong price. Currently, there is a running process of assessment of suitable principles, requirements and methods, which will create base of codes supporting sustainability of construction works. The aim of this 3rd International Conference is to deepen the discussion about problems of the ecological quality of the built environment and the exchange of ideas within the broadness and complexity of this topic. All contributions should deal with problems of the design and the prediction of healthy, comfortable, and economically effective indoor environment. Highly appreciated are contributions that help to create the framework for better implementation of ecological principles into existing technical specifications, legislation and building practice. This international Conference is sponsored by the Scientific Grant Agency of the Slovak Ministry of Education and the Slovak Academy of Sciences through the project no. 1/3324/06, the EC within its Marie Curie Scheme and organized in line with the activities of the Technical Committee 112 - Sustainable Building of the Slovak Standards Institute. Herewith we would like to cordially invite all professionals in the areas of building physics, HVAC, EIA, architects, engineers, designers, building managers, developers, investors and last but not least the representatives of the state and local administrations, science and research to attend this small, but fine event.