Green buildings must meet clear technical expectations in terms of energy efficiency, use of water, and air quality, among other factors. They also must meet occupant needs for comfort, satisfaction and productivity, and may impact occupant mood and health. Moreover, occupant response to building systems may have a significant effect on the technical outcomes. We are presenting a series of case studies of residential and office green buildings that address these issues.Three case studies from the U.S. include: 1) methods and outcomes of several Post Occupancy Evaluations of LEED Gold office settings in Philadelphia. These assessments address issues related to architectural design, engineering systems, and human behavior, and focus on areas where user satisfaction and energy efficient performance can be improved; 2) an engineering, design and behavioral assessment of a LEED Platinum luxury high rise rental building. Methods include instrumentation to measure water and energy use in individual apartments as well as interviews and questionnaires with residents addressing specifics of their use patterns and perceptions of and satisfaction with the building. Data will be presented on outcomes for this specific building as well as their usefulness in creating agent based models to predict satisfaction; 3) report on ongoing research concerning the potential health benefits to a lower income population that may accrue from living in an Energy Star certified affordable housing development. The population living in this building live in an area in which some chronic health conditions are epidemic - such as obesity and asthma. Both of these conditions may be able to be effected by living in a green building, and this presentation will describe the methods and outcomes of a study to assess whether there is any noticeable impact.The 4th case study presents a field study from Austria of summer use of passive housing and user behavior. In discussions about strengths and weaknesses of passive housing, possible overheating in summer is a main critical point. A field project supported by Wienerberger AG asked about user behavior and satisfaction in passive housing under summer conditions. Ten apartments in three passive housing estates of Salzburg City, Austria, were analyzed. Participants received a diary form and were asked to evaluate three times per day their subjective living room temperature, humidity and air quality, and to record their sun shading and ventilation behavior without behavior briefings. Temperature/humidity loggers were installed in the living and sleeping rooms of every apartment. For every estate, an outside temperature logger profile was obtained. Results for these evaluations and recommendations based on the findings are presented.