Abstract The built environment is responsible for 40% of the global energy demand (1). To reduce building energy consumption, regulations are enhancing the appeal of sustainable constructions. Nevertheless, the rate of construction is low in most of developed countries. Efforts are to be made in existing buildings, namely in office buildings, which are statistically more energy-consuming than residential buildings (3). To conduct an adapted energy retrofitting, an energy audit can be realized as a pre-study. The first step is to realize an inventory of fixture of the building equipment. From that analysis, the building behavior and consumption are modeled with the help of dynamic simulation software. A comparison with the real life energy consumption guides the study to obtain a model close to reality. Energy retrofitting plans can then be created, based on this model and on the inventory of fixture phase. If technically adapted, each retrofitting solution is evaluated in terms of investment cost and energy savings. Building energy audits and recommendation phases are not unique and normalized procedures. More advanced and complex calculations and measurements can improve the result accuracy. Nevertheless, the introduced approach gives a first understanding of a building, by analyzing its strengths and its weaknesses. As a result, the proposed retrofitting solutions are suited to each specific building. This renovation plan can then be used as a first-decision making tool for the various stakeholders included in the retrofitting project. Abstract The built environment is responsible for 40% of the global energy demand (1). To reduce building energy consumption, regulations are enhancing the appeal of sustainable constructions. Nevertheless, the rate of construction is low in most of developed countries. Efforts are to be made in existing buildings, namely in office buildings, which are statistically more energy-consuming than residential buildings (3). To conduct an adapted energy retrofitting, an energy audit can be realized as a pre-study. The first step is to realize an inventory of fixture of the building equipment. From that analysis, the building behavior and consumption are modeled with the help of dynamic simulation software. A comparison with the real life energy consumption guides the study to obtain a model close to reality. Energy retrofitting plans can then be created, based on this model and on the inventory of fixture phase. If technically adapted, each retrofitting solution is evaluated in terms of investment cost and energy savings. Building energy audits and recommendation phases are not unique and normalized procedures. More advanced and complex calculations and measurements can improve the result accuracy. Nevertheless, the introduced approach gives a first understanding of a building, by analyzing its strengths and its weaknesses. As a result, the proposed retrofitting solutions are suited to each specific building. This renovation plan can then be used as a first-decision making tool for the various stakeholders included in the retrofitting project. Abstract The built environment is responsible for 40% of the global energy demand (1). To reduce building energy consumption, regulations are enhancing the appeal of sustainable constructions. Nevertheless, the rate of construction is low in most of developed countries. Efforts are to be made in existing buildings, namely in office buildings, which are statistically more energy-consuming than residential buildings (3). To conduct an adapted energy retrofitting, an energy audit can be realized as a pre-study. The first step is to realize an inventory of fixture of the building equipment. From that analysis, the building behavior and consumption are modeled with the help of dynamic simulation software. A comparison with the real life energy consumption guides the study to obtain a model close to reality. Energy retrofitting plans can then be created, based on this model and on the inventory of fixture phase. If technically adapted, each retrofitting solution is evaluated in terms of investment cost and energy savings. Building energy audits and recommendation phases are not unique and normalized procedures. More advanced and complex calculations and measurements can improve the result accuracy. Nevertheless, the introduced approach gives a first understanding of a building, by analyzing its strengths and its weaknesses. As a result, the proposed retrofitting solutions are suited to each specific building. This renovation plan can then be used as a first-decision making tool for the various stakeholders included in the retrofitting project.