The paper presents the results of research focused on evaluating the influence of the architectural design of apartment buildings located in different locations in Havana city. The object under study has been the volume of buildings in relation to their surroundings, which determines the relationship between indoor and outdoor spaces and how indoor spaces are exposed to daylight and solar radiation. Three urban areas were selected taking into account the opinion of some architectural experts. The apartment buildings were classified according to their architectural volume, considering the transitional spaces: streets and corridors, yards and indentations. Sixty six indoor spaces linked to different transitional spaces with varied dimensions, proportions and orientation were chosen to take temperature measurements and make daylight simulations. The comparative assessment of the results considered the difference between the indoor temperature and that measured in an external reference point, mainly at night, when the family is at home. The temperatures taken in the reference points confirmed the effect of the urban heat island. The best transitional space from the thermal point of view is the corridor type. On the contrary, yards offer the worse conditions, except in compact urban areas as Centro Habana. Regarding daylight, no studied space meets the minimum daylight requirement established by Cuban daylight standards, and only one achieves minimum uniformity. The best transitional space is also the corridor type, which guarantees a higher percentage of daylight with respect to an unobstructed outdoor space on a roof. Based on these results, urban form generated from detached buildings separated by corridors is more appropriate for the warm and humid climate of Havana than the compact colonial urban model, although it was considered a good option in studies carried out twenty years before. These results reinforce some conclusions reached at during the last ten years regarding the advisability of reducing land occupancy in current compact urban areas and to avoiding the use of small yards to provide daylight and natural ventilation in apartment buildings. (C) 2012 Elsevier Ltd. All rights reserved.