Åtgärder för energieffektivisering av vanliga småhus - En teoretisk fallstudie av en 70-talsvilla

Sammanfattning: The construction and service sector currently accounts for over one-third of Sweden's total energy consumption. Energy issues are at the forefront, and society is striving for more sustainable development. At the same time, electricity prices are increasing, leaving many households with expensive bills for heating their houses. A significant portion of Sweden's houses were built during the later period of the Million Programme, specifically the 1970s, with 436,000 small houses being built within a span of 10 years. Many of these houses do not meet today's standards or requirements regarding energy efficiency, as a significant amount of energy was lost through transmission and ventilation. Given that many of these houses are already in need of renovation due to aging, it provided an opportunity to implement energy efficiency measures simultaneously. The aim of this work is to provide professionals and private individuals with knowledge on how they can invest in energy efficiency measures for their houses. Through a literature review, a typical 1970s small house was developed for this study. Relevant energy efficiency measures were identified for the building envelope, heating and ventilation system, and the potential for self-generated energy. The developed prototype house was simulated using VIP-Energy, and each measure was studied in the cities of Malmö, Stockholm, and Sundsvall. The simulation results provided the amount of energy saved in kWh/m2 per year. To determine the most cost-effective measures based on energy savings, an approximation of the economic aspect was conducted. The analysis yielded investment costs, payback periods, and savings over 1, 10, and 50 years. To investigate whether private individuals implemented cost- and energy-efficient measures in their small houses, a quantitative survey in the form of a questionnaire was conducted. The results showed that the measures that resulted in the most significant reduction in energy consumption were window and door replacements, installing some form of heat pump, and installing an exhaust air heat pump. These were also the measures that provided the highest long-term savings for the house. For self-generated energy, solar thermal collectors reduced the house's energy consumption the most. However, it was solar panels that provided the greatest long-term financial savings. One of the conclusions drawn was that the cost of local electricity prices greatly influenced the profitability of energy efficiency measures for households. The survey responses showed that private individuals chose the correct measures for their small houses in terms of energy efficiency and long-term economic viability. The exception was the ventilation system, where private individuals chose the measure with the lowest investment cost. The results are beneficial for both private individuals and professionals. Providing the right conditions for individuals to make informed choices not only benefits household finances but also society as a whole. If all households reduce their energy consumption, it collectively contributes to lowering Sweden's overall energy usage, bringing us one step closer to sustainable development.