The construction sector has now entered the ‘Digital era’, and professionals are slowly getting familiar with many of these innovative technologies. This paper shows how such innovations improve the investigation phase when it comes to energy retrofits on heritage buildings. More specifically, multi-view photogrammetry and wireless sensor networks can facilitate the implementation and enhance the relevance of building hygrothermal and energy simulations: photogrammetry quickens up the reproduction of the building geometry whereas wireless sensor networks facilitate and enlarge the collection of data relative to the existing behaviour of an occupied building. This paper explores the benefits of using those two technologies compared to more traditional solutions, regarding data quality and general workflow. In this purpose, two case studies from research projects ongoing in Belgium are briefly described.

Click here for the full version, p. 156.

The HISTool is a software-based tool for the analysis of the current building status, and a decision support tool for the innovative and sustainable renovation specifically of Gründerzeit buildings. These were built between 1840 and 1918 with partially standardized designs and components in CentralEuropean cities. The tool is designed to be applied particularly in the preparation and decision-making stage of renovation projects in the Gründerzeit building sector, prior to the actual planning phase. For the decision-making process, it is essential to provide solid data on different renovation options in an early phase based on life-cycle costs, without a lot of calculation effort. The calculation is based on a model of the building, which consists of 40 elements according to the specifics of Gründerzeit buildings and the selection of predefined renovation measures. The integrated energy performance and life-cycle cost calculation leads to the derivation of life-cycle costs of different renovation variants. A comparison of life-cycle costs of different renovation options leads to information-based renovation decisions. The aim is to stimulate the Gründerzeit sector in the real estate market to implement more energy-efficient and innovative renovations, which are compatible with the specific requirements of historic buildings, and to contribute to the fulfilment of the climate-protection goals. HISTool particularly reflects the environmental and economic goals of sustainable management of historic buildings according to EN 16883, and supports the planning and decision making procedure in the first phase as well as in the detailed planning phase when it comes to the selection of specific measures and assessment against the initial project targets.

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The paper presents desktop analyses of potential energy savings in historic buildings, carried out using standard boundary conditions for calculation of energy savings, as prescribed in the European building energy performance certification schemes. Internal insulation of the building’s façades can potentially reduce the theoretical energy demand for space heating by 9 to 43 % compared to the energy demand of the original building if installed moisture-safe. Combined with other commonly used energy saving measures, 43–78 % reduction of the energy demand was estimated.

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Energy retrofit of historic buildings is a relatively new task in the construction sector. It is therefore important to offer reliable solutions to practitioners and end-users that prevent any undesired outcome. Often, the lack of trust and awareness of the available solutions is limiting the extent of interventions. This has a negative effect on the final energy savings and occupants’ comfort, important factors when it comes to the use and conservation of historic buildings. The Atlas will provide an international collection of exemplary case studies that go beyond current practice in their scope and in depth of information provided. This unique collection of experience from all over the world will allow architects and building owners to browse through best practice examples and find the most relevant information to pursue their own renovation. The purpose of this paper is to show and discuss the need for such a repository as well as the functions and possibilities of the database.

Click here for the full version, p. 238.

Before deciding how to improve the energy efficiency of historic buildings by applying thermal insulation, an estimation of consequences, e.g. changes in heat and moisture flux, must be made. In the EU-project RIBuild, attempts have been made to cluster historic building materials; enabling a user to choose an appropriate material and include uncertainties. Unfortunately, the decisiveness of properties depended on whether e.g. conditions at external or internal surface of the brick wall were considered.

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This paper describes a methodology for assessing damage threshold criteria. The methodology includes a survey and determination of threshold values for deterioration, which can then be used to evaluate the risk in specific structures of external walls. The work includes summarizing existing knowledge and adapting and developing models for failure modes based on field and laboratory testing. Failure modes include frost damage of the exterior façade layer, rot and mould growth within the building envelope and adjoining structures, as well as discolouring of façade surfaces due to biological growth.

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The paper aims to investigate criticalities and potentialities of the Italian Cultural Heritage Ministry’s Guidelines (October 2015) and the European Guidelines for Improving Energy Performance of Historic Buildings (EN 16883 – June 2017), comparing and applying them to selected case studies. The documents represent an instrument to help public authorities and designers to follow an iterative retrofit process; in both cases it is possible to notice some difficulties in their technical application. Thus, we have identified their critical and positive features through the case studies assessment. The scope is to underline possible issues and to suggest new solutions in both cases, improving the existing guidelines with other targets to obtain a calibrated evaluation method, which could guide the retrofit project.

Click here for the full version, p. 285.

The paper aims to present innovative studies concerning removable devices for enhancing thermal performance or mitigating criticalities in listed buildings. The first concerns a “high tech” curtain studied for preventing air drafts from the windows, causing different forms of decay in the Sala delle Asse in Castello Sforzesco (Milano), world known for the Leonardo Da Vinci fresco. The second body of research deals with a new type of “arazzo” (removable and usable seasonally) to improve the insulation of the walls. The study case regards the collection of historic “arazzi” in Sala della Balla, in Castello Sforzesco as well.
The focus is to investigate how the main properties of the removable devices  affect the thermal exchange with the air and the surfaces where they are applied. A third study case is a masterpiece of listed modern architecture, Casa del Fascio in Como, where the new uses require cooling with the addition of a shadowing system.

Click here for the full version, p. 129.

The present paper analyzes the renovation project of a heritage medieval building located in the city center of Bolzano–the “Waaghaus”. The building has been used as case study in the EU-project 3encult, where it has been extensively studied both from heritage and energy efficiency points of view. Our analysis, partly based on the experience gained in the EU-project, aims at validating and improving the renovation project that was developed by a design team commissioned by the owner. In particular three aspects of the renovation are mainly investigated: 1) Reduction of the energy demand 2) Indoor climate and air quality 3) Hygrothermal risk in critical points. Results show that the proposed renovation cuts the energy demand to 60 percent. Moreover they demonstrate that, when renovating a historic building, it is crucial to carefully investigate the ventilation strategy and the critical construction details. Not considering these two aspects can lead to poor air quality and to a significant risk of surface mould and condensation formation.

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Historic buildings account for more than one quarter of Europe’s existing building stock and are going to be crucial in the achievement of future energy targets. In order to ensure their endurance, conservation compatible solutions are needed. Nevertheless, some alteration in the climate is already certain and therefore the impact of climate change on retrofitted historic buildings should be considered in terms of occupants’ comfort, heritage conservation, and energy performance. Inappropriate interventions might weaken the potential of original passive climate adaptive system, such as thermal mass and night cooling, leading to higher risks of overheating. Similarly, retrofit solutions will change the moisture dynamics of historic envelopes, which might lead to moisture damages when combined with more extreme precipitation events. This paper reviews recent literature that provides evidence of climate change’s impact on retrofitted buildings, reveals potential future risks, and thereby throws light on new factors influencing the retrofit decision-making process.

Click here for the full version, p. 62.

Energy efficiency policies might have a negative impact on the heritage values of buildings, an issue widely recognized in Sweden during and after the extensive energy efficiency programme ‘Energy savings plan for existing buildings’ (EBB 1977–84). The purpose of this paper is to assess the long-term impact of the EBB on an urban district in Gävle, Sweden. The district comprises 69 single- and multi-family detached houses built between the 1920’s and 1950’s. Using archival sources and field studies we describe how the buildings have been modified and trace the role of the EBB on the district as a whole. The results show that despite that the EBB has had a major impact on the district, it is difficult to disentangle its role in relation to other factors. The study raises concerns over the common approach in policy making to draw distinct lines in the sand between heritage and non-heritage buildings.

Click here for the full verison, p. 193.