Evaluation of Energy Efficiency in Educational Buildings

The facility strategy of the City of Espoo emphasises improvements in the energy efficiency and efficient use of buildings. This means i.e. improving space efficiency and increasing operating times. Increasing the use of facilities often increases energy consumption. For this reason, the targets i.e. energy savings and increased use of facilities may partly be contrary to each other if individual buildings are considered. In order to encourage relevant efficiency efforts, it is essential to know how to measure energy efficiency, especially in the building operational phase. The aim of this dissertation is to increase knowledge about the evaluation of energy efficiency in educational buildings. The dissertation studies three research questions. The first question provides an overall picture of energy consumption and assesses the factors that are used in evaluating measured energy. The second question explores ways in which building usage and occupancy influence the measured energy consumption and energy cost. The third question examines the ability of alternative indicators to function as comparative indicators in improving energy efficiency. The research was conducted by exploring the issues in existing educational building. The energy efficiency was examined in a statistical and multiple case study approach. The study started with a broad survey in order to generalize the results to a building stock and then, in the second phase, focused on qualitative case studies to collect detailed views from the building stock to help explain the initial quantitative survey. Results showed that the energy consumption of the studied buildings varied considerably regarding all studied factors when examining both building types and individual buildings. The variation cannot be explained only by the factors themselves. Results showed that energy efficiency can be measured by using alternative indicators and confirmed that different indicators make a different impact on results showing efficiency. The choice of indicators to use depends on the needs of the indicator user, as well as the situation and the objectives of the analysis. This dissertation suggests using a set of indicators. In the future, the assessment of the energy efficiency of the operational phase should include, beside physical characteristics, parameters describing building use such as occupant levels, operating times and space efficiency. In addition to technical measures, the City of Espoo can also optimise the need of spaces of daycare centres and schools. The dissertation suggests developing energy audits to take into account the energy efficiency perspective, not only the perspective of energy savings.