Every building experiences a air exchange with the exterior through the micropores of its enclosures (walls), to a greater or lesser extent, depending on the nature of the material with which it is built, there are materials more porous than others.
Being the main objective to obtain a good level of comfort inside the house or flat (in general of any building), it is important to control the air inlet and outlet, especially if it is the hot summer air, to maintain an interior comfortable temperature during the day and night and at the same time achieve it by natural means to save money on electricity bills, energy for the planet and have a sustainable home.
A few simple measures in the design of the house will help you. As we know, the hot air of the months of July and August enters the house at the southern facade Likewise, if we take advantage of the fact that hot air always rises, it will be very advantageous if your house has natural mechanisms to evacuate these airs So that they do not accumulate inside and overheat the house, simply a few ducts from the basement to the roof deck and higher still will serve for this air to escape there when ascending, it is what we commonly know in Spain as a vent.
Any opening (doors and windows) that you open to the house should be strategically located so that once it is opened it will serve to "remove" that hot ventilation from the house.
On the other hand, the air entering the North side It is colder, so the windows on this facade of the house will allow fresh air to pass through, while others strategically located, together with the "vents", will draw out the hot air, with these measures it will be possible to maintain a comfortable temperature without air conditioner or using it less time and less cold.