Large share of Swedish building stock were built during 1940-1980 when people were not fully aware of the energy efficiency concept. Majority of the buildings that made energy declaration are in energy class E-G, which are considered as high energy consumption buildings with low energy performance, and only few buildings meet the Swedish requirements for near zero energy buildings which are in energy class A-C. The energy renovation rate of the existing buildings is low and more needs to be done to make the Swedish building stock energy and resource efficient. In this thesis the potential of energy efficiency improvement is investigated for an old multi family house built during the Million program in Sweden. Passive energy renovation measures on the demand-side along with active energy renovation measures on the supply-side were investigated together with their combinations resulting in eight different cases. The investigated demand-side refurbishments are additional attic floor insulation and replacement of windows with insulated glass windows while the supply-side refurbishments are rooftop PV installation and conversion to water-based heating system with GSHP. The results of this study show that combination of all four energy efficiency measures has the highest energy-saving potential and yields the highest NPV compared to the other cases for an assumed real discount rate of 3% and grid purchase price of 1.60 SEK/kWh, while requiringthe highest CAPEX. On the other hand, GSHP with water-based heating system requires two times lower CAPEX, however, has high energy-saving potential and yields high NPV. / En stor del av Sveriges byggnadsbestånd byggdes under 1940-1980, då folk inte var fullt medvetna om energieffektiviseringskonceptet. Större delen av byggnaderna som har upprättat energideklaration är i energiklass E-G vilket anses vara byggnader med hög energibrukning med låg energiprestanda och endast ett fåtal byggnader uppfyller de svenska kraven som ställs för nära noll energi byggnader som är i energiklass A-C. Energirenoveringstakten i de befintliga byggnaderna är låg och mer behöver göras för att göra Sveriges byggnadsbestånd energi- och resurseffektivt. I detta examensarbete undersöks potentialen för energieffektivisering i ett äldre flerfamiljshus som byggdes under Miljonprogrammet i Sverige. Passiva energirenoveringar som avser energiefterfrågesidan såväl som aktiva energirenoveringar som avser energiförsörjningssidan undersöktes tillsammans med deras kombinationer, vilket resulterade i åtta olika fall. De undersökta energirenoveringarna som avser energiefterfrågesidan är tilläggsisolering av vindbjälkslag och byte av fönster till isolerglas medan energirenoveringarna som avser energiförsörjningssidan är installation av solceller på taket och konvertering till vattenburen värme med bergvärmepump. Resultatet av denna studie visar att kombinationer av alla fyra energieffektiviseringsåtgärder har den högsta energibesparingspotentialen och ger den högsta NPV jämfört med de andra fallen för en antagen real kalkylränta på 3% och ett elpris på 1.60 SEK/kWh, samtidigt som det kräver högst CAPEX. Däremot, bergvärmepump med vattenburen värme kräver två gånger lägre CAPEX, samtidigt som det har hög energibesparingspotential och ger hög NPV.

The rise in population causes serious issues in larger cities since the electrical grid is becoming overloaded. Simultaneously, the demand on more sustainable energy production and the use of renewable energy sources increase. Renewable energy based off-grid electrical systems are a possible solution to decrease the magnitude of these issues. The purpose of this thesis is to compare solar cells, solar thermal collectors and PVT (Photovoltaic thermal hybrid solar collectors) and design the most suitable combination of solar panels for a selfsufficient multi-family house in Jönköping, Sweden. The solar panels were compared from a cost and energy production perspective, then a suitable renewable energy system with all three types of panels was constructed and optimized using Opti-CE, which is a MATLABbased software. During the course of this thesis, an interview was made with Hans-Olof Nilsson who is a co-founder of Nilsson Energy and owner of a self-sufficient off-grid house. The results show that PVT-panels have higher energy production per area and 22% higher LCC (life cycle cost) than regular solar cells in combination with solar thermal collectors. Optimization results indicate that the house cannot be self-sufficient by installing solar panels on the given roof area only, rather the area of installed solar collectors should be increased to a minimum of 1497𝑚2 . With the given roof area of 900𝑚2 the house can only be self-sufficient a maximum of 75% of the time. The results also indicate that the introduction of compact systems with the simultaneous decrease of cost will make renewable off-grid energy systems more attractive in the future.