Volume 23, Issue 2 -

The Swedish National Research programme for Energy Efficiency in historic buildings was initiated in 2006 by the Swedish Energy Agency. This article gives an overview of the programme: objectives, projects and the general results of the programme. The research programme aims to develop knowledge, methods and technical solutions that contribute to energy efficiency in historically valuable buildings without destroying or damaging the historical value of the buildings, including decoration, furnishings, interiors or equipment. The programme is not limited to listed and monumental buildings but covers a wider range of historic buildings that account for a large part of the energy use in the building sector. For one and two-family houses, around 25 % of the energy use is associated with buildings built before 1945. The same number for multifamily houses is around 15 %. The programme is currently in its third consecutive four-year-stage. Previous four-year-stages were completed in 2010 and 2014. Over time, the scope of the programme and the projects have developed from mainly dealing with indoor climate control in monumental buildings towards addressing more general issues in the much larger stock of non-listed buildings. Technical research, based on quantitative analysis, dominate throughout all three stages, however most projects have had interdisciplinary components. The results from the programme have been presented in 31 journal papers, 67 conference papers, five books and five PhD theses. The projects have also contributed to CEN standards and resulted in a number of Bachelors and Master’s theses. An equally important long-term effect of the programme is that the number of Swedish researchers in the field have increased from practically none in 2007 to 18 senior researchers and twelve PhD students from ten universities in 2014. The research programme on Energy Efficiency in historic buildings is unique in an international context. Hopefully it can serve as an example for other countries on how to address an important interdisciplinary research challenge.

In recent years, thermal performance improvements have been applied to an increasing number of historic buildings towards the achievement of the legally binding Scottish carbon dioxide (CO 2 ) emission reductions. Over 20 % of the built environment in Scotland was constructed pre 1919 and the targeting of fabric improvements in these buildings can pose a performance risk if inappropriate measures are applied. This paper discusses through a case study a Building Performance Evaluation (BPE) approach used in conjunction with the design process for refurbishment of a community owned historic building, located in Arisaig, Scotland. The community received funding to improve the energy performance of this nineteenth century stone building and committed to a 75 % reduction in CO 2 emissions. BPE was conducted in 2014 as part of the design process and repeated post-refurbishment in 2015 to validate the design. The initial BPE identified high heat losses, inefficient heating and lighting systems that resulted in occupant discomfort, high running costs and consequently the loss of a community facility during the winter months. The resulting BPE quantified improvements to the building fabric, occupant comfort and reduced energy consumption, which advocated this design approach as a beneficial tool for informing historic building refurbishment.

Local voluntary groups often play an important role in the day-to-day care for historic churches, therefore the perspective of laypersons is very relevant for their conservation. In this paper, we investigate laypersons’ valuation of historic buildings, their experiences of thermal comfort in those buildings and contrast this with their views on the appropriateness of energy efficiency measures. This paper presents four case studies of medieval churches in Groningen, Netherlands. We applied interviews and photo-elicitation to investigate the values held by local committees that take daily care of the churches in our sample. Our theoretical contribution lies in the combination of valuation studies and heritage approaches. Valuation studies is used to investigate the values that are attached to historic buildings by various stakeholders. We apply the ‘heritage-as–a-spatial-vector’ approach which focuses on using heritage as a resource and to position heritage in relation to developments in society. We conclude that for a more balanced assessment of historic buildings, laypersons’ valuations should be further integrated in heritage studies. In particular, community values and comfort needs should be more fully addressed in value assessments.

In restoration work, the compatibility between old and new building material is the key point for sustainable repair of buildings or monuments. Consequently, conservation scientists are looking for an alternative method to the traditional procedures to determine the aggregate grading curve and the binder/aggregate-ratio of the historic material. The problem of using the traditional methods is the frequent major intervention in an existing building. These destructive methods are not allowed. Whereas, to get information about the historic mortar, a new technique, the digital image analysis (DIA), is applied in this paper. Moreover, small amounts of the historic material have already been prepared as thin sections and analysed with a microscope. Modern microscopy techniques allow investigations of quantitative and qualitative composition of historic material. Incentive of this work was to get all the required information to recreate the historic mortar by using the DIA with an open source program only at one thin section. In addition, to examine the accuracy and the significance of the DIA, all results were compared with a known mixture, and in a second test series, the results of the DIA were compared with the traditional methods. The results show that the DIA of thin sections of a historic mortar is highly effective for analysing decisive factors like the binder/aggregate-ratio and the grading curve of the aggregates. Furthermore, it is possible to analyse the mortar only by having one thin section using an open source program ImageJ. Especially in the case of carbonate rock as aggregate, DIA is the only method to analyse these characteristics of a mortar.