Method of selecting an architecture for an electrical cabinet, said electrical cabinet comprising at least one module (16, 17, 18) wherein a plurality of functional electrical units are housed, said functional electrical units being arranged along a separation plane of the module (16, 17, 18) delimiting: - a first cold thermal zone formed by a first space of the module (16, 17, 18) situated on a first side of the separation plane, and - a second heating thermal zone formed by a second space of the module (16, 17, 18) situated on a second side of the separation plane, characterised in that the method is implemented by computer and comprises the following steps: - searching, from data related to the electrical cabinet, among a plurality of architectures proposed for the electrical cabinet, for a so-called passive architecture for which the temperature inside each first and second thermal zone (E1, E2) of the or of each module (16, 17, 18) is lower than a predetermined setpoint temperature for said thermal zone (E1, E2), without injection of cooling power inside the cabinet, and - if a so-called passive architecture is identified: ∘ selection of the so-called passive architecture, - if a so-called passive architecture is not identified: ∘ searching, from data related to the electrical cabinet, among the plurality of proposed architectures, for a so-called economical architecture for which the predetermined setpoint temperatures for each of the first and second thermal zones (E1, E2) of the or of each module (16, 17, 18) are achieved by injection, into the first thermal zone of at least one module (16, 17, 18) of the electrical cabinet, of a minimal cooling power, and o selection of said so-called economical architecture. - a first cold thermal zone formed by a first space of the module (16, 17, 18) situated on a first side of the separation plane, and - a second heating thermal zone formed by a second space of the module (16, 17, 18) situated on a second side of the separation plane, - searching, from data related to the electrical cabinet, among a plurality of architectures proposed for the electrical cabinet, for a so-called passive architecture for which the temperature inside each first and second thermal zone (E1, E2) of the or of each module (16, 17, 18) is lower than a predetermined setpoint temperature for said thermal zone (E1, E2), without injection of cooling power inside the cabinet, and - if a so-called passive architecture is identified: ∘ selection of the so-called passive architecture, ∘ selection of the so-called passive architecture, - if a so-called passive architecture is not identified: ∘ searching, from data related to the electrical cabinet, among the plurality of proposed architectures, for a so-called economical architecture for which the predetermined setpoint temperatures for each of the first and second thermal zones (E1, E2) of the or of each module (16, 17, 18) are achieved by injection, into the first thermal zone of at least one module (16, 17, 18) of the electrical cabinet, of a minimal cooling power, and o selection of said so-called economical architecture. ∘ searching, from data related to the electrical cabinet, among the plurality of proposed architectures, for a so-called economical architecture for which the predetermined setpoint temperatures for each of the first and second thermal zones (E1, E2) of the or of each module (16, 17, 18) are achieved by injection, into the first thermal zone of at least one module (16, 17, 18) of the electrical cabinet, of a minimal cooling power, and o selection of said so-called economical architecture.