Life cycle assessment of a single-family residence built to either conventional- or passive house standard

The environmental and resource impacts of wooden single-family residences designed to meet the conventional Norwegian Building Code from 2010 (TEK10) and the Norwegian passive house standard NS 3700 are compared using life cycle assessment. Four different heating systems are evaluated for the two building designs: (1) electric (resistance heating), (2) electric and wood, (3) electric and a solar heat collector and (4) electric and an air-water heat pump system. The goal of the research is to evaluate the different ways of lowering the total environmental burden of a building's life cycle, considering the two building standards, and evaluating the impacts due to implementation of renewable heating systems in comparison to standard Norwegian systems largely based on electricity.The life cycle results show that the wood-framed single-family residence built according to the passive house standard provides a consistent and clear reduction of cumulative energy demand of 24–38% in comparison to the conventional building standard TEK10 with electric panel heating. In combination with efficient heating systems, a passive house building envelope with a heat pump system provides the largest savings, an improvement of almost 40% compared to a conventional house with electric heating. The reduction in greenhouse gas emissions of the cleanest design compared to the standard alternative is almost 30%. Solar heated water also provides substantial environmental gains for the passive house. On the other hand, a standard building envelope with a heat-pump system reduces impacts to a level comparable to that of a passive house building with only electric heating.

► Complete life cycle environmental impacts of single family residences assessed.
► Passive house building envelope reduces impacts by ca. 20%.
► Air-water heat pump system also reduces impact by ca. 20%.
► Combined reduction of 27% is achieved.
► Solar thermal energy achieves similar benefits in passive house.