This study presents an in-depth analysis of 69 case studies focusing on the energy retrofit of historic buildings, uncovering challenges, best practices, and lessons learned to balance energy efficiency improvements with heritage preservation. The findings highlight several challenges encountered during renovations, such as complex heritage evaluations, restrictions on alterations, coordination issues with authorities, technical limitations, higher investment costs, and knowledge gaps. On the other hand, identifying factors promoting renovation, including demonstrating energy savings while respecting heritage, early collaboration between planners and authorities, and quantifying investments, could incentivize owners and authorities. The limitations of a still-limited sample size, occasional incomplete data, and potential sample bias call for cautious interpretation of the presented analysis. Despite these, the study provides valuable insights into successful projects, emphasizing the need for scalability, knowledge transfer from innovative policies, and targeted policy-making for successful replication. The study concludes with a call for further development of the HiBERatlas (Historic Building Energy Retrofit atlas), an extensive resource for historic building renovation, expanding its database, collaborating with agencies, and tailoring guidance for stakeholders to foster energy retrofits in heritage buildings.

This study explores the influence of uncertain boundary climate conditions on the hygrothermal performance of an internally insulated historic masonry wall using numerical simulations. The research compares diverse internal and external climate data sources to evaluate their reliability. A pre-validated hygrothermal simulation model serves as the benchmark for comparing simulated data with actual monitoring data. An array of climate data sources, including adaptive indoor climate models defined in the EN 15026 and UNI EN ISO 13788 standards, Typical Meteorological Years, and ground weather station data are considered. The core assessment parameters are temperature and relative humidity values beneath the insulation. Unexpectedly, the findings reveal that external climate conditions have a minor influence on the simulation results. Conversely, internal climate conditions significantly impact the outcomes, causing substantial variations. These implications underline the criticality of selecting an appropriate indoor climate model and moisture load class. The incorrect choice can lead to substantial errors, with peak relative humidity values predicted by the models varying in a range greater than 15 percentage points of relative humidity. In conclusion, the study reveals that utilizing Typical Meteorological Years and adaptive indoor climate models still yields excellent results, despite the inherent uncertainties. Moreover, this study emphasizes the importance of carefully selecting suitable indoor climate models to enhance the accuracy of hygrothermal simulations in historic buildings and underlines the need for future research focused on developing more precise guidelines for identifying the correct moisture load classes.

Farbige Photovoltaik mit und ohne strukturierte Oberflächen bietet ganz neue Möglichkeiten der Integration in Situationen, in denen man anderenfalls aus gestalterischen oder anderen Gründen davon absehen würde.
Ein Beispiel? Stilfs hat als Dorf eine sehr differenzierte Dachlandschaft – und dank seiner Steilheit sind die Dächer gut erreichbar für die temporäre Einrichtung von Photovoltaik-Musterflächen und gut sichtbar für die
Betrachter – DIE Gelegenheit also, um am realen Beispiel zu sehen, wie innovative Photovoltaik wirkt.

Deshalb sind wir mit dem Kurs "Neu trifft auf Alt" am Samstag, den 16. September 2023 beim Streumarktes in Stilfs zu Gast. Er richtet sich insbesondere an Architekten, Ingenieure und Fachinstallateure, die mehr über die
Integration von Photovoltaik im historischen Kontext erfahren möchten.

An die Einführung und Vermittlung des nötigen Know-Hows zum Einsatz farbiger Photovoltaik, schließt eine Dorfrunde an, bei der wir an unterschiedlichen Dächern mögliche Umsetzungsvarianten sehen und diskutieren
können. Mit dabei ist auch die Landeskonservatorin Dr. Karin Dalla Torre.

One of the main targets of SHC Task 59 is to provide a solid knowledge base on deep renovation of historic buildings. The Historic Building Energy Retrofit Atlas (HiBERatlas, www.hiberatlas.com) provides a bestpractice database of exemplary energy efficient  interventions in historic buildings. The database presents bestpractice examples of how a historic building can be renovated to achieve high levels of energy efficiency while respecting and protecting its heritage significance.

This handbook follows the systematic approach outlined by the European standard EN 16883:2017 Guidelines for improving the energy performance of historic buildings. It describes how the standard can be applied in practice with chapters on heritage value assessment, building survey and holistic assessment of energy efficiency measures. The book draws on the experience from a team of international leading experts in the field of energy efficiency in historic building.

Historic building restoration and renovation requires sensitivity to the cultural heritage, historic value, and sustainability (i.e., building physics, energy efficiency, and comfort) goals of the project. Heat recovery ventilation can contribute to the mentioned goals if ventilation concepts, and airflow distribution is planned and realized in a minimally invasive way. Compared to new buildings, the building physics of historic buildings are more complicated in terms of hygrothermal performance. In particular if internal insulation is applied, the need for dehumidification is needed for robust and risk-free future use, while maintaining the building’s cultural value. As each ventilation system has to be chosen and adapted individually to the specific building, the selection of the appropriate system type is not an easy task.

Climate change imposes great challenges on the built heritage sector by increasing the risks of energy inefficiency, indoor overheating, and moisture-related damage to the envelope. Therefore, it is urgent to assess these risks and plan adaptation strategies for historic buildings. These activities must be based on a strong knowledge of the main building categories. Moreover, before adapting a historic building to future climate, it is necessary to understand how the past climate influenced its design, construction, and eventual categories. This knowledge will help when estimating the implication of climate change on historic buildings. This study aims at identifying building categories, which will be the basis for further risk assessment and adaptation plans, while at the same time analyzing the historical interaction between climate and human dwelling. The results show some correlations between building categories and climate. Therefore, it is necessary to use different archetypes to represent the typical buildings in different climate zones. Moreover, these correlations imply a need to investigate the capability of the climate-responsive features in future climate scenarios and to explore possible further risks and adaptation strategies.

Purpose Improving the energy performance of historic buildings has the potential to reduce carbon emissions while protecting built heritage through its continued use. However, implementing energy retrofits in these buildings faces social, economic, and technical barriers. The purpose of this conceptual paper is to present the approach of IEA-SHC Task 59 to address some of these barriers. Design/methodology/approach Task 59 aims to achieve the lowest possible energy demand for historic buildings. This paper proposes a definition for this concept and identifies three key socio-technical barriers to achieving this goal: the decision-makers’ lack of engagement in the renovation of historic buildings, a lack of support during the design process and limited access to proven retrofit solutions. Two methods – dissemination of best-practice and guidelines – are discussed in this paper as critical approaches for addressing the first two barriers. Findings An assessment of existing databases indicates a lack of best-practice examples focused specifically on historic buildings and the need for tailored information describing these case studies. Similarly, an initial evaluation of guidelines highlighted the need for process-oriented guidance and its evaluation in practice. Originality/value This paper provides a novel definition of lowest possible energy demand for historic buildings that is broadly applicable in both practice and research. Both best-practices and guidelines are intended to be widely disseminated throughout the field.

What Americas Cup and a heritage building have in common They both aim at innovative technologies and cutting-edge solutions. The owner of the project, an ex-crew member of the most famous sailing match race in the world, pushed the planning team to develop extraordinary solutions for his house. The house, Villa Castelli, is an historical listed building located on the Como lake. During its history, it has been transformed many times, giving as results a non-uniform structure composed by different construction technologies. The aims of the owner were: an overall refurbishment particularly focused on energy efficiency, the exploitation of renewable energy sources based on-site production and a fixed budget. To reach these goals, the energy needs have been reduced improving the performance of the thermal envelope. Then, the building’s technical systems have been re-developed in order to exploit as much as possible available renewable energy sources. From the very beginning, it was clear that, for finding optimal solutions, a multidisciplinary approach was necessary. The design approach should be the result of a shared approach integrating different fields, such as creative design, technology, knowledge of material properties, building physics. The great synergy among building envelope retrofitting, innovative technological solutions and the deployment of renewable energy sources allows the transformation of this historical listed building into an outstanding example of a nearly zero energy building (nZEB).

Research and development of high thermal insulation materials for the construction sector requires an accurate characterization of the wall's performance, since that is the main causes of thermal exchanges between the internal and external boundaries. This paper presents a test procedure developed within the EU Project EFFESUS for evaluating the steady-state thermal performance of a masonry wall. A large-scale mock-up of the inhomogeneous wall was tested in a guarded hot box (GHB) apparatus before and after the application of an aerogel-based material. The methodology proposed in this paper is structured in the following steps: (i) definition of the wall geometry and the percentage of stone and mortar, using walls’ photographic records and geometrical surveys; (ii) precise thermal characterization of the material used; (iii) hygrothermal assessment procedure based on infrared technology (IRT) survey, gravimetric test, and monitoring of the internal relative humidity (RH); (iv) steady-state and dynamic thermal simulation; and (v) detailed set-up of the test using the data retrieved from the thermal surveys and simulations. According to the results of IRT surveys and the dynamic simulations, the mock-up was divided into thermal homogeneous parts, verifying the uniformity of the surface temperature and the heat flux in an isothermal area. This approach was validated both for low and high energy performance walls. Results show that the thermal flux was reduced to one third after the application of the aerogel.

Research and development of cost-effective, high-performance thermal insulation materials for the construction sector has to be focused on their final application. In particular, solutions for refurbishing historic buildings, which represent 40% of the European building stock, have to offer a good compromise between environmental quality, energy efficiency and conservation aspects. In this paper, the experimental assessment of an insulation material based on aerogel technology, recently developed in the European project EFFESUS, is presented with regard to the material's thermal performance, compatibility with historic fabric and reversibility. The overall results obtained in laboratory testing on a real-size mock-up and in a real-world case application indicate that the new material is a promising solution for retrofitting historic buildings, thanks to its thermal properties, easy application, reversibility and material compatibility.