Abstract Indirect evaporative cooling systems (IECS), characterized by the use of wetted roof or wall surfaces for cooling without increasing the indoor air moisture, consist of an interesting bioclimatic strategy is still little explored in Brazil. The paper aims to evaluate the use of a particular form of IECS (which combines evaporative cooling and thermal mass brought about by a water reservoir) for indoor thermal control in warm conditions in Curitiba, located within Bioclimatic Zone 1. Two scale models were initially built, monitored and compared to each other: a control module (CM) and an experimental module (EM), the latter provided with an evaporative pond. A subsequent configuration of the system which cancels out the evaporative function of the system, based on the increase of the roof's thermal capacitance by an enclosed water container, was tested in a second monitoring round. Thus the results showed a higher effectiveness of the IECS for the indoor cooling of the tested scale-models.