An important measure for climate change mitigation is reduction of energy use in buildings worldwide. In 2010 Skanska Sverige AB began designing an office building in the southern parts of Sweden, aiming towards a Net zero energy building (Net ZEB) balance. The construction work started in the middle of 2011. In the beginning of 2012 Sveriges Centrum för Nollenergihus/the Swedish Centre for Zero-energy buildings (SCNH) published a Swedish definition for a zero-energy building in the Swedish climate. In short; the Swedish definition of a zero-energy building demands fulfilment of the passive house criteria, and that a zero energy balance must be reached over a year based on import/exported balance. This study summarises the overall design ideas, constructions, installations, energy balance of the office building and investigates whether the building reaches the zero energy-building definition according to SCNH. The simulations show that a Net ZEB balance may be reached. However, the passive house criterion is not reached. The study discusses pros and cons in the Swedish definition of “zero-energy building”/Net ZEB and suggests clarifications needed and possible amendment that may be implemented in an updated version of the definition.

It is important to minimize transmission heat transfer losses through the building envelope when designing and building energy efficient buildings in heating dominated climates. In such a climate, a large part of the space heating demand is caused by transmission heat transfer losses through the building envelope. Calculations of these losses must be carried out in a correct way to ensure a properly sized heating system and a good indoor climate. Furthermore, underestimating the transmission heat transfer may lead to energy costs that exceed expectations. A Swedish study was published five years ago which concluded that the state of knowledge was low and simplified methods used were not accurate. Five years has passed since the previous study. The purpose of this follow-up is to investigate whether the state of knowledge among Swedish consultants has increased and to review the progress within the international field. The study shows that little has changed in Sweden. The state of knowledge regarding different measuring methods and the effect on thermal bridges is still not satisfying. Furthermore, the review of recent research shows that the relative effect of thermal bridges vary greatly. More guidelines and education/training are needed. Further research should be carried out with a holistic approach where thermal bridges are investigated with varying construction types, energy efficiency of building envelopes and different measuring methods.

An increasing demand for energy-efficient buildings has led to an increasing focus on predicted energy performance once a building is in use. Many studies have identified a performance gap between predicted energy use and actual measured energy use once buildings are in the user phase. However, none of the identified studies normalise measured energy use for both internal and external deviating boundary conditions. This study uses a Net-zero energy building (Net ZEB) building in Sweden to test two different approaches to the normalisation of measured energy use—static and dynamic methods. The normalisation of energy use for a ground source heat pump reduces the performance gap from 12% to 1–5%, depending on the method of normalisation. The normalisation of energy from photovoltaic (PV) panels reduces the performance gap from 17% to 5%, regardless of the method used. The results show that normalisation is important in order to accurately determine the energy performance of buildings. The most important parameters are the indoor temperature and internal loads, which have the largest effect on normalisation in this case study. Furthermore, the case study shows that it is possible to build Net ZEB buildings with existing technologies in a Northern European climate.

One of the greatest challenges for the world today is the reduction of greenhouse gas emissions. As buildings contribute to almost a quarter of the greenhouse gas emissions worldwide, reducing the energy use of the existing building stock is an important measure for climate change mitigation. In order to increase the renovation pace, there is a need for a comprehensive technical documentation that describes different types of buildings in the existing building stock. The purpose of this study is to analyse and describe existing residential buildings in Sweden. The data are based on published reports from 1967 to 1994 that have not been publicly available in a database for other researchers to study until now. Data from the reports have been transferred to a database and analysed to create a reference for buildings and/or a description of building typology in Sweden. This study found that there is a rather large homogeneity in the existing residential building stock. However, it is not possible to use a single reference building or building technique to cover the majority of the existing buildings. In Sweden, common constructions for exterior walls in multi-dwelling buildings which should be used for further studies are insulated wood infill walls with clay brick façades, lightweight concrete walls with rendered façades and concrete sandwich walls. The most common constructions for one- and two-dwelling buildings are insulated wooden walls with clay brick façades or wooden façades. Furthermore, roof constructions with insulated tie beam and roof constructions where the tie beam is a part of the interior floor slab are frequently used and should be included in further studies.