With the support of the TOBUS software, it is now possible to evaluate, in a methodical and rigorous manner, one of the major causes of obsolescence for office buildings. The functional obsolescence is a major parameter affecting technical installations and influences the value of an office building. The tool can be used during an office building audit to examine and assess all the building services which are likely to be found in modern buildings (i.e. heating, ventilating and air conditioning (HVAC) plants, fire fighting services, electrical installations, information networks, building management systems, etc.). The selected quality assessment criteria correspond to the requirements of modem buildings, including compliance with user needs, flexibility, divisibility and maintainability, as well as conformity with building regulations, Moreover, the software is used to pet-form an exhaustive diagnosis of the entire building, including architectural and technical aspects, and supports the user to define and evaluate different scenarios and retrofitting actions, providing the corresponding costs.