ENERGIEFFEKTIVISERING FÖR ÄLDRE SMÅHUS : Energibesparing och lönsamhet för olika åtgärder i ett äldre småhus från 1976 i Avesta kommun

Purpose: This study aims to investigate the profitability of various energy efficient measures and at the same time examine the energy savings for an old house from the 1970s. Method: The methodology of this work is based on field measurements, observations, and document analysis. The calculations that were performed were monthly calculations performed in Excell. The data were then collected and analysed and provided the house's energy balance. The profitability of different measurements was then determined according to its payback period. Results: The house's estimated energy use for heating is about 22.1 MWh / year. With rock source heat pump, approximately 70% energy saving was achieved. With FTX-system, an energy saving of about 23% was achieved, while the replacement of windows & doors and additional insulation of exterior walls and attic achieved the same energy saving of approximately 14%. Economic analysis showed that installation of a ground source heat pump can be the most profitable alternative, according to the payback period and long-term analysis, which is an analysis over 40 years ahead. The results also showed that energy prices have a significant effect on the profitability, where doubled energy prices almost halved the payback period and at the same time tripled the economic profit after 40 years calculated with the prerequisites in the current study. Conclusions: For the current house, the replacement of windows & doors is recommended instead of the additional insulation because in associating with the replacement of windows & doors, the air leakage due to leaks can almost be halved, which would benefit a possible installation of FTX systems in the future. After doubling energy prices, some measures have given a return of more than 70%. Therefore, based on the data presented in this work, it is recommended to, in addition to the payback period, also make a long-term analysis to have a more stable basis when deciding what measures should be taken to reduce the purchased energy. This is because when comparing different energy saving investments, it is almost impossible to justify when considering only the payback period. It is also recommended that in an older one family houses with similar prerequisites, the bedrock heat pump should be installed first if there is no need for renovation. This is to maximize the energy savings and thus the financial gain