As is well known, between two bodies with different temperatures, heat is transferred from the warmest to the coldest. Something similar happens in winter from the inside of the building to the outside cold air, but also in the summer, from the outside hot air to the cooler interior of the building. Thermal insulation of the building slows down the speed of heat exchange of the building with the environment through the surfaces (walls, roofs, floors, doors, windows).
Thermal insulation of a building essentially provides it with a "protective casing" so that in winter it reduces the rate at which heat escapes from the building and in summer reduces the rate at which heat is introduced into it. This reduces the energy consumption of the various heating and cooling systems of the buildings. The most common heat-insulating materials prevent heat flowing into and out of the building because they contain indoors air trapped either in fibers (eg fiberglass) or in closed cells (eg expanded polystyrene). The thermal insulation capacity of each material is different.
A building must be insulated on all its exterior surfaces, vertical and horizontal, enclosing air-conditioned areas from which heat energy may escape. The most essential parts of a building that need to be insulated are:
