Sustainability in office buildings: a comparison in the measurement of environmental impacts

Users and not buildings are responsible for environmental degradation. Even if the in-use phase of building life cycle consumes more resources, the construction industry has principally focused on design and construction stages. Several studies carried out energy evaluation of office buildings to improve environmental impact, but energy is just one component. Moreover, most efforts have focused on technologies, which improve buildings’ efficiency, but over the long term the effectiveness depends on users’ behaviours. Therefore, sustainability science needs a solution-oriented approach to explain the complex human-nature interaction in the built environment during the in-use stage of office buildings. To overcome the gap, the present research develops a model, based on a sustainability index, namely Ecological Footprint (EF). The objective of the method is to identify the environmental impact of office buildings during their in-use stage by highlighting the effects of users’ behaviours and occupancy. The model is based on nine addenda (Built-up, Energy Consumption, Water Consumption, Material Consumption, Food & Drink, Mobility, Waste Generation, Recycle Potential, and Occupant). To test the model, the present research interviews the facility managers of three companies on year 2020 data. The comparison demonstrates the importance of monitoring users’ behaviours to minimise office buildings footprints. Indeed, in all case studies the Food & Drink addendum represents a high percentage of the total footprint. The main limit of the research is the collection of data. All the facility managers found it difficult giving data about consumptions of a specific asset, as they have some general expenditures for consumption. Moreover, other information, such as the amount of hours each employee spends in the building, are collected in different ways and makes it hard to define a standard procedure for data collection. Therefore, the paper comments on the results and gives back some possible overcomes of the limits.