As architects we must come up with ideas that put natural light, ventilation, and comfort as a first; regardless of the type of housing. But in these times that we must stay in our homes, natural light is essential for our physical and emotional health. So we analyze one of the bedrooms of a 40-year-old house, which has something particular and is that it is enclosed by 4 walls. What does not allow natural light, due to its absence of windows, more than just "chiltepes" (name given to perforated or decorative bricks in this area). This has caused the appearance of mold and the elevated internal temperatures of the bedroom in summer times (summers of 38 ° C). Proposing thus a flared window, which allows the natural light to be distributed inside the bedroom, these types of windows allow a greater penetration of light into a space, but if it is used with pronounced openings, such as the proposed window, taking into account the bottom an angle that allows natural light to go to the bottom of the room.