The 4^th expert meeting in working phase was held at LBNL, Berkeley, USA on September 19-21, 2011. We had 32 participants from 13 countries.

At first, the overall research plan was introduced and the latest action plans were confirmed. In the Task force session, the attempts and improvements of describing occupant behaviors in both residential and office buildings were presented and the challenges were highlighted. In Subtask B1 session, the progress of case studies was introduced and a formatted source book for case buildings was proposed. In Subtask B2 session, the online databases from USA, Germany, and Spain were presented. In Subtask C session, review for statistical analysis of energy use was presented and the outline of this research was discussed. In Subtask D session, the action plan was discussed and the typology, sensitivity analysis, and model related to occupant behaviors were presented. In Subtask A session, the revised three level definition databases for building energy use and occupant behaviors were introduced and discussed. At last, the progress of each subtask was presented; the status report of this project was intensively discussed and came to an agreement.

We had a fruitful discussion through the three-day meeting.

The 5^th Expert Meeting in Working Phase will be held in Netherlands on April 25-27, 2012.