Lifecycle primary energy analysis of conventional and passive houses

In this study we analyse the primary energy implications of thermal envelope designs and construction systems, for a 4-storey apartment building, including the full lifecycle phases and the entire energy chains. We maintain the architectural design of the reference building, and alter the thermal properties of the envelope components and include heat recovery of ventilation air to achieve buildings with thermal properties similar to three existing passive houses in Sweden. We also vary the building frame material from the reference wood case to reinforced concrete, and vary the heat supply system between district heating and electric resistance heating. We follow the lifecycle of the buildings and analyse and compare their lifecycle primary energy use, considering the production, operation and end-of-life energy uses. The results show that the lifecycle primary energy use of a passive house building is substantially lower when it is heated with district heating instead of electricity. A passive house with district heating uses 42–45% less lifecycle primary energy than the same house with electric heating. Lifecycle primary energy use is 2–4% less when a passive house is constructed with a wood frame instead of a concrete frame. This study shows that material choice becomes increasingly important as buildings are made to the passive house standard and as efficient heat supply systems are used.