The importance of the envelope in building consumption

The thermal envelope of a building is composed of all the enclosures that separate habitable spaces from the outside, and also by the interior partitions that divide the habitable spaces from the non-habitable spaces that limit with the exterior. Among these last ones would be the storage rooms or the garages. Ultimately, it involves all the elements that are responsible for separating the interior from the exterior of a building, such as walls, ceilings, floors, or windows.

What objectives does the thermal envelope of a building have?

The envelope of a building has two main tasks: its protection and climate control. This allows thermal insulation of the property, protecting it from climate-related adverse conditions and increasing the well-being of its inhabitants. In addition, insulation is the fundamental variable that defines the demand for energy consumption of the building's climate control. Thus, I will achieve that my building is more or less sustainable in energy terms.

As is logical, when a building does not have a good thermal envelope, in addition to being an uncomfortable place for its inhabitants, it leads to higher and less sustainable energy consumption.

What are the elements of the thermal envelope of a building?

Although in the previous section we have already mentioned some concepts, it is time to learn about the elements that make up the thermal envelope of a building, they are as follows:

• Roofs: These are the upper enclosures that are in contact with the air.
• Facades: This is another exterior enclosure that is in contact with the air. Facades can have six different inclinations: north, south, east, west, southeast, and southwest.
• Floors: These are the horizontal lower enclosures that are in contact with the ground or with a space that is not habitable.
• Party walls: These are the enclosures that are between two buildings and are a common division for both. When the building is built later, the enclosure is considered a facade.
• Thermal bridges: These are areas of the thermal envelope where there is a loss of efficacy. This can be due to various causes, such as the union of several enclosures, a smaller thickness, or a different composition.
• Interior partitions: These are those constructive elements both horizontal and vertical that serve to divide the interior of the property into different spaces.
• Ground contact enclosures: These are all those enclosures that are in direct contact with the ground and that we have not mentioned yet.

How are the envelopes of a building classified considering their thermal behavior?

It is clear that the envelope of a building is vital for it to be efficient and for its inhabitants to enjoy comfort inside. Furthermore, in addition to the classification you have seen so far, they can also be classified by the way they behave thermally and by the value of their characteristic parameters.

Enclosures that are in contact with air:

• Opaque: These are the roofs, the walls of the facades, the floors that are in contact with the air, and the integrated thermal bridges.
• Semi-transparent: The windows and doors located in the facades and the skylights in the roofs.

Enclosures that are in contact with the ground:

• Walls that are in contact with the ground.
• Floors that are in contact with the ground.
• Roofs that are buried.

Interior partitions that are in contact with non-habitable spaces

• Interior partitions that are not in contact with a non-habitable space, with the exception of sanitary chambers.
• Floors that are in contact with sanitary chambers.

The thermal envelope of a building is the key to achieving efficient consumption. To ensure that this is as low as possible, the envelope must always be designed (and as much as possible, also executed) by an expert company in this area of sustainable architecture, since both the design and the precise arrangement in execution of all the elements mentioned is crucial to achieve an envelope as effective as possible in insulating the interior spaces from the external climatic conditions.