The contractors in the Swedish construction industry persistently struggle to build according to the energy requirements which are outlined in the project. These requirements are both based on the client needs and national regulation and standards. Type of the project delivery system has also a significant impact on the implementation of these requirements. These requirements are easier to fulfill in the design-build contract as both the design and construction processes rely on a single contractor responsibility. However, in the design-bid-build delivery systems that the construction company has limited impact on the design process of the buildings implementation of these requirements seems to not be a straightforward task. Nevertheless, in practice, the contractor is the main responsible firm for the implementation of these energy requirements. To address these requirements, construction companies carry out energy assessments which are based on the work routines that may be unique for each construction company. In this study the energy assessment of five Swedish construction companies has been investigated in order to develop a new work routine for the Peab Sverige AB. The result of this investigation demonstrates that the energy assessment varies in these construction companies upon the amount of work carried out internally in the organization. Hereupon, some of the construction companies employ external consultants support in order to complete the work routines (energy assessment). This mainly initiates from the lack of time, lack of knowledge as, in some cases, a product of poorly designed work routine. The similarities between these construction companies are that they comply an input list which defines the parameters that affect the energy assessment. This input list is later used for energy assessment through simulation programs such as IDA-ICE and VIP-Energy. Finally, based on the results of this investigation a new work routine is developed in Microsoft Excel in order to facilitate collaboration between different actors involved in the project. The new work routine that was developed for Peab Sverige AB gathers the essential data for the energy assessment and reduces the amount of effort and time required in the past. The work routine is based on two technological aspects which simplifies the work: (1) An input template where all the required inputs are collected, (2) a manual that provides guidelines on how a standard 3D-model shall be designed (i.e. the required information that shall be stored in the 3D-model) and also the essential data for assessment of the building’s energy use.