This paper presents an experimental investigation on the effects of 14 different configurations of partitions on the natural convection heat transfer in enclosures. The reduced scale test cell is fitted with the partition between two vertical hot and cold isothermal walls. The remaining walls of the enclosure are insulated. The experiments are conducted using air as the working fluid over a Rayleigh number range from 6 x 10(7) to 1.5 x 10(8) with an aspect ratio (height/length) of 0.5. Correlations for the tested configurations are reported, and the percentage reduction in heat transfer for each case is compared to the case of a single room. (C) 2000 Published by Elsevier Science Ltd. All rights reserved.