Kvarteret Kajutan - Från lågenergi till plusenergi

Sammanfattning: Energy and environmental demands regarding buildings have become an increasingly discussed topic, both in Sweden and in Europe as a whole. The general trend indicates that greater efforts are being put into the energy efficiency of the built environment. There are already numerous examples of houses with a low energy demand, and the number of low energy buildings is constantly growing. At the time being, the maximum level for energy demands for housing in Stockholm is 110 kWh/m 2year, but as soon as next year the limit will be changed to 90. The Swedish agency Energimyndigheten is currently conducting a project to interpret the EU Directive on the so-called Nearly zero energy buildings, and the preliminary results indicate that the level of requirements for purchased energy will end up with about 55 kWh / m 2year, which is in line with today’s recommendationsfound in FEBY's Kravspecifikation för Passivhus. Starting with a low-energy house in Henriksdalshamnen in Stockholm, we have analyzed various energy-efficiency measures and their influence on power and energy needs. The financial aspects associated with the measures have been studied using a model of life cycle costs. The measures were initially studied individually to give an idea of how much impact they each had. Three packages of measures were then put together, where the most energyand cost-effective solutions were included. The first package of measures aimed to achieve the standard for Passive houses, and was accomplished by the replacement of windows and an improvement in airtightness. The economic analysis showed that this package was not viable. The second package of measures aimed to as much as possible reduce the building's energy needs and at the same time demonstrate profitability. The results showed a more than halved energy demand and the economic calculations indicated that it even turned a profit. Finally, the possibility of installing energy-producing systems in order to achieve a plus energy house was studied. The idea was to examine whether it was possible to cover up the need for purchased energy by using solar and wind power, while maintaining profitability. The analysis shows that this would be difficult to achieve, primarily because of the high investment costs entailed, and the difficulties associated with the regulations regarding the sale of energy.