Daylighting can improve well being and human health, as also energy can be saved by reducing its need for electric lighting, cooling and heating. Exterior obstructions, building design and daylight system are the key elements to improve the use of natural light. This paper presents partial results from a Master’s dissertation developed at Universidade Federal da Paraiba. The aim of the study was to investigate the daylighting potential of residential spaces illuminated by pass-through and conduction daylight components, designed considering the Brazilian building regulation. A series of computer simulations were used to analyze the building performance, using the software Daysim. A number of 160 simulations were ran, associating two residential rooms (kitchen and bathroom) and six design variants: protruding and enclosed balcony; balcony’s depth (1,20; 1,50; 2,00; 2,50 e 3,00 meters), maximum plot ratio allowed, ground level and 4 storey high level; North, East, South, and West facade orientations. Useful Daylight Illuminance (UDI) is the performance indicator. About 42,5% of the kitchen’s models and 75% of the bathroom’s models presented low illuminance levels. Protruding or enclosed balcony, floor level, window size (based on floor’s area) and position affects the daylight levels in rooms.