In modern offices, the heat load per floor area has increased. With high cooling loads, the possibility
of draft problems increases. The purpose of this article was to study the flow patterns and draft risk in
an office environment where cooling and air distribution is implemented with active chilled beams. The
study is based on experiments in a laboratory mock-up room in three load conditions: summer, winter, and
midseason (spring/autumn). Thermal plumes from heat sources and warm or cold windows had a notable
effect on the flow pattern and velocity distribution in the occupied zone. Areas with increased draft risk
were found in locations where the supply jet turns down to the occupied zone. Draft risk can also be high at
the floor level as a result of a circulating flow pattern in the room. This article concentrates on measurement
and modeling results in a single-person office room. Comparisons are made with corresponding results in
an open-plan office.