A certain difference can be noticed in the lumps of energy-saving houses that use solar energy for heating, which is dictated by the conditions described above. This difference prompted theorists to create the concept of "solar architecture".
Shape of the building, as well as the elements of the structure, in addition to the basic tasks, it is to promote the energy efficiency of the building and heat gains from insolation. Thus, the shape determines not only the functional and aesthetic aspects, but also about the building's energy consumption.

In the literature on heating and building physics, you can meet the analysis of basic solids in terms of energy demand for heating buildings.

The shape and formation of the building, and the demand for heat:
a) shape of the building, and the heat demand - Q, with constant cubature - V and almost constant building area - F,
b) increase in heat demand - Q, when doubling the cubature - V.,
c) addition (connection) cubature module, and the heat demand Q w %

For objects of various forms, and constant cubature V = 10 m3 heat demand is calculated - q; the smallest have compact objects, close to a sphere or a cube, but in turn they are exposed to much greater air infiltration than object no 1.

Dependence of heat demand on the proportion of sides at constant cubature - V.

The above analyzes are helpful, but they do not take into account the benefits of insolation and the optimization of the body in conjunction with solar techniques. So, the assessment of architectural solids only in terms of minimizing the covering surfaces and glazing is inappropriate and only limits the development of "solar" architecture.
The body of solar houses should be shaped like this, that its maximum area is on the south side, on which the elements of solar systems are located. The aim is to minimize external surfaces on the north side, to reduce heat loss. As a result, solids are created on the rectangular projection, trapezoid or triangle, long side facing south. "Solar" houses using passive methods are heavily glazed (Open) on the south side, a very closed (windowless) on the north side.
The interior space of houses using passive systems is shaped in various ways, depending on the type of premises. Rooms located in the southern zone, open to insolation, are usually single-space, without clear divisions closing a given function in a separated cubature. The heated air can circulate freely, by heating sleeping quarters in the northern zone. Excess heated air can be released to the outside. Building a home , one-roomed ”, where most of the spaces are connected, both vertically and horizontally, there is a danger of accumulation of warm air in the topmost part of the house, while creating a feeling of coolness in its lowest parts. Separate and closed volumes should be located in the northern zone (buffer). The gradation of daylight and temperature coincides with the spatial arrangement of the interior of the house. Connecting individual rooms with similar thermal requirements allows you to solve the internal space of the house, meeting the requirements of energy efficiency and functionality at the same time.