For thermal comfort, the building must act as a barrier, transforming the outdoor climate to conditions suitable for indoor activities; the typical design process is a weighing of conflicting demands to reach a satisfactory compromise, such as between passive and active climatization, between privacy and solar access, between cross-ventilation and noise reduction, etc.
The climatic design process requires special attention. In 1974 the Building Research establishment in the UK was aware that a building can’t be design satisfactorily exclusively on economic, functional or formal grounds, just slightly adjusting to give a good indoor climate, since climate must be taken into account when deciding on the overall concept of a project, on the layout and orientation of buildings, on the shape and character of structures, on the spaces to be enclosed and the spaces between buildings. In other words, climate must be considered at the early design stage. \citet{al1974} distinguished between three stages in climatic design:
-       forward analysis, which includes data collection and ends with a sketch design;
-       plan development, which includes the design of solar controls, overall insulation properties, ventilation principles and activity adaptation;
-       element design, which comprises closer examination and optimization of all individual building elements.
In the following section of the chapter, all the parameters that have to be considered during the design stage will be analyse in depth in both the climate locations assigned, so to define some passive strategies to reduce as much as possible the energy need for heating, cooling, ventilating and lightning.
Surroundings
The surroundings of a building have great influence on its indoor climate, whether it is in a city or in the countryside, providing for or protecting from certain winds, creating solar access or shading, etc, must be considered in each individual case.
Form
The form of the building includes its main proportions, scale/volume, attachment etc. Roof form is often discussed; in fact, cylindrical and dome roofs have a higher heat transfer coefficient and larger area than flat roofs of the same base. As a result, the solar energy absorbing area is nearly the same, whereas the convection heat transfer area is higher for the curved types. The ceiling height is another issue related to roof form.
Orientation
A North-South orientation of the main facades is preferable, since the summer sun penetrates façades and openings only marginally in these directions, while in winter when the path of the sun is lower, there is possibility of solar access.
Materials
Building materials may be different for different building elements and they may play a greater role for the overall thermal performance. A standard recommendation is that local materials should be used as far as possible. However, the choice of materials should take into account, not only the production, transportation and construction costs and energy, but the life-cycle cost of the building, including the operation and the demolition and possible recycling of the material.
Ventilation
Thermal comfort can be created by increasing air speed through cross ventilation, which promotes evaporative cooling of moist skin. In addition, the placement of openings for inlet and outlet of air is essential for directing the air current to the occupation zone and the presence of ventilated attic spaces, preferably with some ceiling insulation, reduce radiative heat transfer from the roof sheeting. Wind angles up to 45° to the openings are acceptable and may even give better ventilation rates than in a perpendicular direction.
        Structural cooling by night ventilation has been commonly adopted in hot and arid regions: during the daytime, a sufficient amount of         internal building mass can serve as a heat sink to absorb, by radiation and natural convection, the heat penetrating into and generated         inside the building. As a rule of thumb, night ventilation can create an indoor maximum temperature of 7–8 K below the outdoor maximum;         during daytime, when the building is closed, the thermal mass is cooler than the indoor air, making the operative temperature lower, further         enhancing the comfort.