The CO2 emissions associated with the construction and operation of public buildings are a significant portion of public building life cycle assessment, which is concentrated in emission time and in absolute emission volume. This chapter discusses results of the case study on “Demonstration Pilot of Consumption/Needs–based GHG Accounting System: The case of public office building.” These include LCA and end use analysis in terms of building construction, operation and human needs which include food, access and electric appliances. Quantification of CO2 emissions related to the services requires the determination of the total GHG emissions induced by the building during its entire lifetime, including the carbon footprint of the building materials, the CO2 emissions related to the building construction and the building operation. This is an important but complex climate and sustainability research domain. The complexity arises first from the need to use a life cycle assessment encompassing the entire value chain for the determination of the carbon footprint of the building materials, with primary data. The second source of complexity is the determination of a suitable metric to measure the performance of the building. Most of the time, for GHG emissions’ performance, an emission rate (GHG emission per unit of time) or an absolute emission volume is used. In the case of a consumption-based approach to GHG accounting of a building, neither of these two metrics is suitable. The most relevant metric is the total GHG emission induced by the building per unit of service it has offered as shelter. A proxy for this metric could be total GHG emissions/(the expected lifetime of the building * the average percentage of occupation by a user * number of users). This chapter discusses the results of a case study on the “Demonstration Pilot of this Consumption/Needs—based GHG Accounting System using the case of public office building.”