A commonly accepted advantage of jalousie windows is their ability to be left part-way open in heavy rains as a way to maintain desirable ventilation, whether a sunshower or prolonged tropical storm. An experiment in 1960 tested the efficacy of jalousie windows in tropical climates to exclude rain while still allowing for air flow. A major issue with excluding rain while allowing air flow is that both tend to come from the same direction. The angled slatted jalousie windows give the impression of solving this issue, however, the actual efficacy of the windows to let in air while keeping out water was deemed unsatisfactory by the study's authors.