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Energy is crucial to the wellbeing and development of nowadays society and will remain important for the foreseeable future. With respect to the type and quantity of energy consumed, significant changes are ongoing and further major changes can be expected in the near future. There are also various policy objectives that shape energy policy, depending on the country context. Among these objectives, the following can be highlighted: minimizing any adverse effects on the climate and on the environment; providing energy access to all; securing energy supply; reducing dependence on energy imports; looking for new energy sources, routes and suppliers that offer local economic benefits; reducing local environmental pollution; driving job creation; achieving low energy costs for society. Key strategic elements to reach such objectives are in particular the gradual transformation of the energy systems from fossil fuels to renewable energy, the increase of the efficiency of the energy systems, the reduction of energy use by consumers, the creation of fully integrated energy markets and the removal of unnecessary regulatory or technical barriers. The information provided in this guidebook aims to contribute to the reaching of the above-mentioned policy objectives. The guidebook is based on the results of a research project carried out within the IEA Energy in Buildings and Communities Programme (EBC) called "Cost-Effective Energy and Carbon Emissions Optimization in Building Renovation (Annex 56)". The guidebook was compiled to raise awareness among the players that can influence policies and standard definition and to engage them in the subjects of energy efficiency and renewable energy sources in the context of building renovation. Existing buildings present a tremendous potential, not only to reduce energy use and emissions, but also on other areas of the political agenda. It is the objective of this guidebook to highlight how energy related building renovation is a policy tool to achieve broad benefits to society., info:eu-repo/semantics/publishedVersion

This guidebook was compiled to raise awareness among the players that can influence policies and standard definition and to engage them in the subjects of energy efficiency and renewable energy sources in the context of building renovation. Existing buildings present a tremendous potential, not only to reduce energy use and emissions, but also on other areas of the political agenda. It is the objective of this guidebook to highlight how energy related building renovation is a policy tool to achieve broad benefits to society, info:eu-repo/semantics/publishedVersion

This guidebook is particularly intended for professional home-owners, i.e. individuals or companies that own and manage residential buildings. It is assumed that these owners are responsible for ensuring maintenance, repair and general servicing tasks and lead the decisions on the improvements to be made regarding comfort, safety, saving energy or just uplifting the buildings to contemporary needs or style. The main goal is to help in the decision-making process towards the optimized renovation of the residential building stock. More specifically, the guidebook provides a framework for the understanding of the relationships between cost-effective building renovation, energy savings and the use of renewable energy sources, highlighting the total added value achieved with the interventions., info:eu-repo/semantics/publishedVersion

The aim of the report is to illustrate the application of the methodology developed within the IEA EBC Annex 56 project and present several tools available for the successive implementation of the several steps of the process. The tools include those that have been used by the participating countries in the selected case-studies and also tools that, although not being used in the IEA EBC Annex 56 project, are compatible with the developed methodology.

To promote energy efficient buildings, with low energy consumption and energy generation onsite, innovative renovation projects are needed that can act as forerunners and inspiration but also serve as best practice examples for the expert audience and the general public. Within this IEA EBC Annex 56 project, six different Case Studies from six European countries were compiled and analysed . The Case Studies are both residential and non-residential buildings, which serve as model projects for renovations in each individual country. The specific aim of the case study activity of this IEA EBC Annex 56 project is to provide significant and useful feedback from practice on a scientific basis.

"Energy in Buildings and Communities Programme, March 2017", Buildings are responsible for a major share of energy use and have been a special target in the global actions for climate change mitigation, with measures that aim at improving their energy efficiency, reduce carbon emissions and increase renewable energy use. The IEA-EBC Annex 56 project «Cost-Effective Energy and Carbon Emissions Optimization in Building Renovation» intends to develop the basics for future standards, which aim at maximizing effects on reducing carbon emissions and primary energy use while taking into account the cost-effectiveness of related measures. The IEA EBC Annex 56 project pays special attention to cost effective energy related renovation of existing residential buildings and low-tech office buildings (without air conditioning systems)., info:eu-repo/semantics/publishedVersion

The relevance of the building sector in the global energy use as well as in the global carbon emissions makes the improvement of the overall energy performance of existing buildings an important part of the actions to mitigate climate changes. Regardless of this potential, large-scale building renovation has been found hard to trigger, with present standards mainly focused on new buildings, not responding effectively to the technical, functional and economic constraints of the existing ones. One of the common problems in the assessment of building renovation scenarios is that only energy savings and costs are normally considered, despite the fact that the investment on energy efficiency yield several benefits beyond the value of saved energy (the so-called co-benefits). To demonstrate and highlight the relevance of co-benefits achieved in the renovation process, a Portuguese neighbourhood with nearly 17.000 inhabitants that has been recently renovated is analysed in search for evidences of the existence of these co-benefits and their relevance. Indoor temperature, humidity and noise insulation were monitored and a survey to the residents was carried out. Results clear indicate the achievement of co-benefits at the building level such as increased user comfort and reduced problems with building physics (mould and water infiltrations), but also the elimination of the feeling of gentrification by outside people to the neighbourhood. The analysis demonstrates that the decision-making process canâ t only be based on investment costs and energy savings, being necessary that owners, investors, promoters, but also policy makers adapt their reasoning to include these additional benefits.

Many regulations and initiatives to promote the reduction of the energy consumption and carbon emissions have been implemented in the building sector. However, they are mostly targeted for new buildings. In order to have an effective impact and reach the goals that are being established, it is necessary to act in new but especially in the existing buildings, which correspond to the majority of the European building stock. Building renovation improves the buildings’ energy performance, reducing the carbon emissions related to the operation of the building but the renovation involves adding new materials and technical systems. The production process of these new materials uses energy (embodied energy) and releases carbon emissions. In this sense, after a certain level of energy efficiency, the materials added to the building may have more embodied energy than the energy savings they will lead to. To evaluate the relevance of the embodied energy in building renovation, IEA EBC project Annex 56, developed a methodological framework to evaluate the cost-effectiveness of building renovation solutions which include a life-cycle impact assessment. In this context and using a particular case study, different renovation solutions are compared with and without considering the embodied energy. The results have shown that the embodied energy do not have a major impact on the evaluation of the cost-effectiveness of the renovation solutions, but as the renovation approach gets closer to zero non-renewable energy level, its relevance increases.

The social and environmental urgency of large-scale integrated retrofitting of the European residential building stock is widely acknowledged and supported by all Member States. However, the European building sector is currently still not able to offer an integral solution for deep renovation toward nearly Zero Energy Building (nZEB) for reasonable costs. MORE-CONNECT project aims to tackle this issue by developing cost optimal solutions to renovate buildings towards nZEB. In this project, the optimal solutions include the development of prefabricated, multifunctional renovation elements for the total building envelope (façade and roof) and installation/building services. This paper presents the first stage of the project, namely the analysis and comparison of three scenarios following the current national requirements in Portugal i) 80% reduction of the current primary energy consumption of the building, ii) cost optimal solution (nZEB) and iii) net zero energy (NZEB). The optimization of the building envelope will be the main driver for the three scenarios as well as the inclusion of renewable energy strategies. Overall, results suggest that it is possible to achieve cost-effective solutions for the renovation of Portuguese residential buildings. Moreover, the cost-optimal solution (scenario ii) matches approximately with the 80% reduction of energy scenario (scenario i)., MORE-CONNECT is funded by the European Commission within the framework of the Horizon 2020 program

Following the impact of the climate changes and their causes, buildings proved to be one of the main responsible for the greenhouse effect due to the carbon emissions related with their construction and use. The recent changes in the European regulations, in a tentative to improve buildings energy performance, are mostly suited to new buildings. However, the majority of the building stock has more than twenty years and renovating it, in accordance with the current standards, can lead to difficult and expensive procedures. Considering the main goals of reducing the use of fossil fuels and the related emissions, the use of renewable energy sources offers an alternative to these deep interventions in the buildings envelope. In a search for the right balance between energy conservation and energy efficiency measures and technologies that require the use of renewable energy, IEA EBC launched Annex 56. The main purpose of the project is the development of a methodological framework that allows comparing renovation scenarios that deeply reduce energy and carbon emissions combining energy efficiency measures and the use of renewable energy. It takes into consideration not only the reduction of the energy use, carbon emissions reductions and costs, but also embodied energy and co-benefits that arise from the renovation procedure. The methodology was applied to a Portuguese case-study that has gone under renovation. The results allow comparing the chosen renovation scenario with other scenarios and justify the option of going beyond the cost optimal solutions in order to have more effective reduction of the carbon emission while still being cost effective.

Promoting the improvement of the overall energy performance of buildings is a relevant part of the European climate action and the Roadmap for moving towards a competitive low carbon economy in 2050, with an expectation of reducing greenhouse gas (GHG) emissions by around 90% when compared to 1990 values, in the area of the built environment. The recast of the European Energy Performance of Buildings Directive (EPBD) introduced the goal of nearly zero-energy buildings (nZEB) for all new buildings from January 1st, 2021 and plans should be drawn to stimulate the transformation of existing buildings that are refurbished into the same concept. EPBD also requires that all European Member States must ensure that the minimum energy performance requirements for buildings are set to achieve optimal levels, i.e. the energy performance levels that lead to the minimum cost during the life cycle. Therefore, Cost Optimality and nZEB are two fundamental concepts within the current European Union policy related to the energy performance of buildings and consequently related to climate change mitigation and non-renewable resources consumption, with Cost Optimality mainly focused on costs and nZEB focused on low energy consumption levels and on site renewables harvesting. In this context, this paper, using two characteristic buildings of the Portuguese residential building stock, aims at presenting the results that emerged from the analysis and identification of the most cost-effective packages of renovation measures needed to adapt existing buildings to zero energy balance and comparing them with those resulting from the calculation of cost-optimal levels.The investigation of the trade-offs between a renovation towards zero energy balance and a cost optimal renovation without energy use restrictions is relevant to provide clues to the development of national plans for increasing the number of nZEB and to provide appropriate financing and other instruments to catalyze this transformation.

The existing building stock encloses a huge potential for actions to deal with climate change and to move towards a sustainable economy, but the decision making process for its renovation keeps hampered by the evaluation of building renovation measures that only considers the direct costs, disregarding other relevant benefits and thus, significantly underestimating the full value of improvement and re-use of buildings, both in local and global economy. The goal of this study was to identify a broader scope of effects that arise from building renovation and to propose a methodology for their quantification and integration in the decision making process in order to assist owners and promoters in the definition of the most appropriate renovation measures. These effects that arise from building renovation operations have been related with the different packages of renovation measures in order to allow comparing and ranking them through a tool developed for this purpose. The application of the developed methodology and tool to a case study allowed to confirm the relevance of the non-financial benefits in the final evaluations, proving that not only economic criteria should support decisions in the field. An enormous influence of the categories related to the social aspects was demonstrated, as well as to the environmental parameters, clearly showing that these parameters can change the ranking between the tested renovation packages.

In order to mitigate climate changes induced by human action, the European Union settled a long term goal of reducing, up to 2050, the carbon emissions to 80 to 95% of 1990 values. At the level of the built environment it is expected to reduce carbon emissions to about 90% of the values of 1990 in that period. In order to promote this achievement, EU established the “nearly-zero energy” buildings concept that emerged in the context of the EPBD recast. This directive determines that by 31 December 2020, all new buildings must be nearly zero-energy buildings and all member states must develop policies and take measures to stimulate the transformation of the building stock also into nearly zero-energy buildings. In the actual context, this is a major challenge since there isn’t yet enough knowhow to do it and the existing standards and regulations regarding energy consumption are mainly focused on new buildings and do not respond effectively to the numerous constraints of the existing ones. It is then urgent to develop new renovation approaches that take into consideration the characteristics and limitations of existing buildings as well as to develop tools and good-practices guides, hold on appropriate, applicable and cost effective technologies, to support the different decision makers involved in this sector. The great challenge is to find sustainable ways of renovate in a cost-effective and massive way the huge and high energy consumer building stock.