The thermal envelope represents a determining element for the thermal comfort of the residents of a building. This, which is also called thermal envelope, consists of the entire set of architectural elements that limit the living spaces of the construction and separate them from the outside, which includes enclosures and partitions. In short, it represents the main barrier between the interior of buildings and the climatic conditions outside them. The objective is for the thermal envelope to be as efficient as possible in fulfilling its task of offering thermal insulation, maintaining thermal comfort in its living areas and promoting energy efficiency.

Among the functions of a thermal envelope, four can be highlighted, the first of which is thermal insulation, to which we must add breathability. On the other hand, protection against wind, so that air currents inside the building are avoided. However, sound insulation and preventing water from entering are two other essential functions. The thermal envelope is nothing more than the skin of the building, which will determine the comfort of the residents and the durability of their spaces.

When talking about the thermal envelope, it is important to identify the spaces that make it up. One of them, and especially important, being the habitable areas. This refers to all those spaces in which residents carry out their daily lives and that have an equivalence in terms of their thermal conditions. On the other hand, the conditioned living space, which requires adequate thermal conditions, such as hallways or stairs.

On the other hand, unconditioned habitable space lacks the need to maintain thermal conditions, although it needs to be habitable, so it has different basic resources, such as lighting. Finally, the fourth type would be the non-habitable space, which has common characteristics. Places such as storage rooms or the garage belong to this category.

The thermal envelope uses a series of elements that allow it to be structured and fulfill its function in the most efficient way possible.