All external elements of the usable housing of the passive building volume still perform the same functions as in traditional houses, but their role has been expanded with new tasks resulting from the need to obtain thermal energy from solar radiation, its storage and conversion into thermal energy. Heat loss by penetration has also been kept to a minimum. These new tasks affect the south wall in a different way, and in another for other external partitions.

A. The walls: Eastern, western and northern
Exterior walls (except the southern) should first of all be characterized by very good thermal insulation. The maximum value of the heat transfer coefficient k should be 0,4 W/m²K, and therefore be much lower than recommended in the Polish standard — 0,75 W/m²K.
The construction of these walls depends on their direct participation in solar heating. If through the upper skylights, or through large southern glazing, the sun's rays are allowed to fall on the north wall and it is an absorbing wall, it should be a wall of the "heavy" type, Ie. with a solid brick structure, concrete, stone, etc.. In case of, when it is an enclosure for auxiliary rooms, it can be a wall of the "light" type, that is, with a frame supporting structure (wood, stood), filled with a thick layer of thermal insulation and covered with wood, gypsum tiles, ceramic cladding, etc..

Cross-sections of houses showing the dependence of the northern wall solution on the passive system solution

Window openings in these walls should also have a low value of the heat transfer coefficient k, especially kef — that is, taking into account the insulation curtains for the night.
Triple glazed window openings should have minimum surfaces that meet only the lighting requirements. These changes affect the north wall. Windows in the eastern and western walls should also meet the above requirements, and at the same time, they should determine to what extent the rays of the setting or rising sun can penetrate the interior of the apartment. East or west windows are more effective in securing vertical blinds against the low shining sun, the position of which can be determined using various auxiliary materials, allowing to determine the angle of incidence of sunlight on a specific day and at a specific time.