Renovering av flerbostadshus - en studie om energieffektivisering och lönsamhet

Sammanfattning: In today’s society a large focus is put on energy systems and how our energy systems are built up. In order to make sure that we in the future still can enjoy the living standards that we are used to today, Sweden and EU have made a number of decisions on making our energy system more energy efficient and consequently reduce the usage of energy resources. By 2020 the European Union should have reduced its energy consumption by 20 % compared to 1990’s level, and by 2050, 50%. The building sector comprises a large part of Sweden’s national energy usage, and therefore strict requirements are put on improvements on the energy usage in buildings, in the near future. The goal of this study is to develop strategies on different energy efficiency measures that building owners can implement when refurbishing multifamily apartment buildings, where the technical energy saving measures and the economic incentives come hand-in-hand.The object of study is a multifamily apartment building in Södermalm, owned by a property owner. The heating of the building comes from district heating. The property is built in 1962 and will in the near future be deeply renovated. Many current heating and ventilation solutions in the building are outdated and there is great potential for improvements.A study visit to the property was carried out in order to investigate the condition of the building and thereby discover where the largest improvement potentials are and to see what energy saving measures, e.g. a supply and exhaust ventilation system with heat recovery, or low energy windows, are possible to implement in the building. The study visit showed that many of the new technologies that can be adopted in general in connection with renovation actually have the possibly to be implemented in the studied property. A wide range of areas where energy effectivising measures could be taken are studied, including old windows that leak large amounts of heat, and the fact that there is no heat recovery in the building.In order to know which measures that are suitable to implement in the studied building, an investigation on different technologies and measures for making buildings more energy efficient was carried out. Both established and traditional measures and new technologies are studied.A model for energy savings have been developed, where a simulation program and energy calculation formulas have been used. The profitability of different energy efficiency measures are analyzed using the Life Cycle Cost, LCC method, using results obtained from the technical analysis. The conclusion made from the results and analysis is that improvements in the energy performance in windows is profitable, and should if possible be made by changing the inner glass to an isolating glass, and in the cases where current windows must be replaced, by changing them to triple-glass windows with a low U-value. If the building owner presupposes a large increase in energy prices in the future, then additional isolation for the façade of the building should also be installed. According to this research a supply and exhaust ventilation system with heat recovery should be installed since this measure led to the largest economic profit.