In an attempt to decrease the preheating time of the basin water of basin type solar stills, a single slope single basin solar still with baffle suspended absorber (SBSSBA) was designed and fabricated using locally available materials. A transient mathematical model is presented for the still. The model uses the lumped system of analysis in which the system is divided into several elements, each of which was treated as a lumped system by itself. The energy balance equations for various parts of the still are solved analytically using the method of Gauss elimination. In order to validate the theoretical model, theoretical and experimental results are compared, and good agreement has been achieved. The effects of vent area and water depth of the upper and lower water columns on the daily productivity of the still were studied. Comparisons of the performance of the SBSSBA and the conventional unit,the single slope single basin solar still (SBSS), have been carried out. It is found that the daily productivity of the SBSSBA is about 20% higher than that of the conventional still (SBSS). (C) 2000 Elsevier Science Ltd. All rights reserved.