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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", The renovation of the existing building stock represents a huge potential in actions to mitigate climate change, not only by the improvement of the overall energy performance of the built environment, but also by the reduction of resource depletion and minimization of waste production related with new construction. Nevertheless, this potential hasn?t been fully explored. Contributing to this, the evaluation of building renovation measures normally considers only the energy savings and the costs, disregarding other relevant benefits and thus, significantly underestimating the full value of improvement and re-use of buildings at several levels of the economy. In IEA EBC Annex 56 project, the reduction of energy use, emissions and global costs are the direct benefits resulting from energy related renovation measures and the notion of co benefits refers to all the other positive or negative effects resulting from those renovation measures., info:eu-repo/semantics/publishedVersion

"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.

A revisão da diretiva europeia relativa ao desempenho energético dos edifícios (EPBD recast), publicada em 19 de maio de 2010, introduziu a obrigatoriedade de todas as novas construções a erigir após 31 de dezembro de 2020 serem edifícios de necessidades quase nulas de energia (nZEB). Devem ainda todos os Estados Membros preparar planos que permitam também aumentar o número de edifícios existentes que se adaptem ao mesmo conceito. De acordo com a diretiva, estes edifícios apresentam um desempenho energético muito elevado e a reduzida energia de que necessitam deverá ser assegurada em grande parte por energia de fontes renováveis, incluindo energia de fontes renováveis produzida no local ou nas proximidades. A significativa indefinição dos vários parâmetros que compõem a redação dada pela diretiva ao conceito deverá ser clarificada por cada Estado Membro. A transposição da diretiva para a regulamentação nacional foi realizada através do regulamento de desempenho energético dos edifícios de habitação, no qual os edifícios com necessidades quase nulas de energia são definidos como sendo aqueles dotados de uma componente eficiente compatível com os resultados decorrentes da aplicação da metodologia de custo ótimo e de formas de captação local de energias renováveis, preferencialmente no edifício ou na parcela de terreno onde está construído, que cubram grande parte do remanescente das necessidades energéticas previstas. Ambas as definições, da diretiva e da regulamentação nacional, apresentam ainda um elevado grau de indefinição, cenário que se verifica repetido em muitos dos restantes Estados Membros da União Europeia. Cumulativamente, as definições não perspetivam qualquer diferenciação entre os edifícios novos e os edifícios existentes, sendo que, para estes últimos, os constrangimentos do ponto de vista técnico e de rentabilidade económica, poderão dificultar de forma relevante a adaptação ao novo conceito. Neste contexto, tendo por base os estudos elaborados para a identificação dos níveis ótimos de rentabilidade do desempenho energético dos edifícios residenciais em Portugal utilizando o quadro metodológico comparativo desenvolvido pela Comissão Europeia, são identificados os níveis ótimos de rentabilidade dos requisitos energéticos aplicáveis na reabilitação do parque residencial português e explorados os conjuntos de medidas que permitem converter esses edifícios em edifícios com necessidades quase nulas de energia. Estas análises permitem dar um contributo para a futura clarificação da definição de edifícios de necessidades quase nulas de energia, com base em critérios de racionalidade económica.

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.

Na Europa, o uso de energia para arrefecimento dos edifícios residenciais, apesar de ainda apresentar uma relevância limitada, tem vindo a crescer nos últimos anos. Em Portugal, também corresponde a uma pequena fração do total da energia usada em edifícios residenciais, mas a expansão da instalação de sistemas técnicos para fornecer arrefecimento é esperada devido à combinação de diferentes razões. Além disso, cenários para a evolução das temperaturas durante as próximas décadas devido às mudanças climáticas indicam que Portugal será um dos países mais afetados na Europa com um aumento de 3,5 a 4 ° C na temperatura média do ar em 2080. Apesar destes dados que fomentam o crescimento contínuo da instalação de sistemas técnicos para fornecer arrefecimento, Portugal apresenta características naturais que podem ser utilizadas para evitar a sua necessidade.

Vila Nova de Gaia, a 300.000 inhabitants municipality in Portugal, has established the goal of transforming their schools into carbon emissions free buildings. The first pilot project shows a combination of cost effective energy efficiency measures with renewable energy harvesting allowing reducing nearly 90% final energy use and carbon emissions.

A urbanização de Vila d’Este é uma das mais importantes urbanizações de “habitação de custos controlados” em Portugal, com um total de 109 edifícios, alojando cerca de 17 mil habitantes. Tendo por base o processo de reabilitação em curso, é realizada uma análise de custos de ciclo de vida. O objetivo é identificar os níveis ótimos de rentabilidade dos requisitos energéticos aplicáveis na reabilitação dos edifícios e em cada um dos seus componentes com relevância no desempenho energético, bem como identificar os níveis de desempenho energético compatíveis com o conceito de edifícios de necessidades quase nulas de energia. Os resultados desta avaliação serão de utilidade relevante para o desenvolvimento do plano nacional para a reabilitação do parque edificado existente como previsto na Diretiva Europeia para o Desempenho Energético dos Edifícios de 2010.

Buildings are one of the major consumers of energy in Europe. This makes them an important target when aiming to reduce the energy consumptions and carbon emissions. The majority of the European building stock has already some decades and so it needs renovation in order to keep its functionality. Taking advantage of these interventions, the energy performance of the buildings may also be improved. In Portugal the renovation techniques, both regarding energy efficiency measures as well as measures for the use of renewable energy sources, are normally planned at the building scale. It is important to explore the possibility of having large scale interventions, has it has been done in other countries, namely at neighbourhood scale with district energy system in order to optimize the results in terms of costs and environmental impact.

A produção e consumo dos vários tipos de energia são dos grandes responsáveis pelas emissões de gases com efeito de estufa que contribuem para as alterações climáticas. No sentido de reduzir as emissões tendo em vista a mitigação das alterações climáticas, o setor dos edifícios, enquanto um dos grandes consumidores de energia, é um alvo de intervenção importante no que concerne à redução dos consumos e consequentes emissões de CO2. Neste contexto, nos últimos anos a Comissão Europeia tem vindo a publicar Diretivas com um grau de exigência crescente em relação ao desempenho dos edifícios, de modo a torna-los mais eficientes , ainda que de uma forma que seja rentável no ciclo de vida do edifício. De modo a perceber o potencial de melhoria de desempenho energético dos edifícios do parque habitacional português, analisaram-se alguns edifícios representativos do mesmo, com e sem medidas de melhoria de desempenho energético, avaliando a rentabilidade do investimento ao Soluções otimizadas de reabilitação de edifícios residenciais para atingir os nZEB 104 longo do ciclo de vida do edifício. Os resultados permitem verificar que as medidas que têm maior impacto são a alteração dos sistemas de climatização e preparação de águas quentes sanitárias e a melhoria do desempenho das fachadas e coberturas. O presente documento foca-se especificamente nas componentes opacas das fachadas, apresentando os níveis ótimos de rentabilidade para o seu desempenho energético em operações de reabilitação de edifícios existentes de diferentes épocas e em diversas zonas climáticas, e mostrando como estes elementos podem contribuir para a obtenção de edifícios de energia quase-zero.

A Comissão Europeia tem criado e atualizado diversas diretivas que promovem a eficiência energética, sendo necessário atuar nos diversos setores de atividade. O sector dos edifícios é preponderante, sendo responsável por cerca de 40% dos consumos finais de energia. Nos edifícios públicos, a melhoria da eficiência pode contribuir para reduzir as despesas assumidas pelos órgãos de poder e melhorar as condições de conforto dos utilizadores. Alguns municípios têm vindo a realizar intervenções de melhoria no parque escolar, não só para proporcionarem melhores condições de conforto aos alunos, mas também para melhorarem o desempenho energético e reduzirem os encargos. Com base no caso de estudo de uma escola básica de tipologia P3, através de uma análise de custos de ciclo de vida, são identificadas as medidas de melhoria do desempenho energético com melhores resultados na redução do custo global. As medidas com impacto mais relevante quer ao nível da redução de custos quer na redução dos consumos energéticos, foram a substituição da iluminação e dos envidraçados. A introdução de isolamento nas paredes e cobertura, apesar do impacto reduzido tanto ao nível dos custos como na energia, afiguram-se, em algumas das soluções testadas, também rentáveis. Tendo em vista o objetivo final de transformar estes edifícios em edifícios de emissões nulas de CO2 eq. até 2020, é possível aferir que: -As medidas de melhoria da envolvente opaca, apesar de pouco relevantes, podem ser, ainda que marginalmente, rentáveis; -A melhoria do desempenho energético de envidraçados e da iluminação são medidas essenciais; -A aproximação ao objetivo de emissões nulas só é atingível com a introdução de sistemas

An existing ruin of a vernacular house located in a rural area of Portugal is being renovated, aiming for architectural identity preservation and low environmental impact, to offer suitable comfort conditions for tourism exploitation. Calculated global energy consumption reduction is 94% of the calculated current energy use of the building

Improving energy efficiency in existing buildings is a great challenge. These buildings have their own limitations related with their design, location and function. To study the possibilities of cost-effectively improve the thermal performance of these buildings and increase the chances of reaching the nearly zero energy (nZEB) target, one building of Rainha Dona Leonor neighbourhood has been analysed. The purpose of the study was to analyse the robustness of the cost optimal methodology when renovating towards nZEB targets. With this work it was possible to understand that the most cost effective package of renovation measures to achieve cost optimal levels and to achieve the nZEB target are very similar and these results do not suffer major changes when variations on the energy prices, discount rates or photovoltaic (PV) costs are considered. However, these changes make the use of PV more cost-effective and nZEB levels become, sometimes, also cost optimal levels.

O presente capítulo apresenta uma metodologia para a determinação das soluções de reabilitação de custo ótimo, ou seja, das soluções que apresentem o menor custo considerando o investimento na operação de reabilitação e os custos de utilização do edifício ao longo do seu ciclo de vida, e demonstra a aplicação dessa metodologia num edifício residencial característico do parque edificado de Portugal., info:eu-repo/semantics/publishedVersion

The European roadmap towards a competitive low carbon economy in 2050 raised the awareness about buildings energy performance due to their potential for cost-effective energy consumption and carbon emissions reductions. For the evaluation of the levels of energy performance of buildings, the European Commission presented the Cost Optimal Methodology allowing comparing different energy performance levels of buildings and buildings components and identifying those with the lowest associated cost considering the building life cycle. This study, using four reference buildings from the Portuguese building stock, where some scenarios for the improvement of their energy performance were analysed with the purpose of identifying the cost-optimal levels, compares the economic performance of different measures. Results provide guidance for the assertive combination of elements for new buildings and for building packages of renovation of measures, as well as for the choice of individual measures in partial renovation scenarios, which, beyond common, are usually performed without the control of the national energy certification system.

"Energy in Buildings and Communities Programme, March 2017", This brochure is a selection of successful realised demonstration projects within IEA EBC Annex56 partner countries that highlights successful solutions and provides general findings, similarities and differences emerging out of the demonstration projects selected in the participating countries. The ?ShiningExamples? are gathered mainly for motivation and stimulation purposes, highlighting the advantages of aiming at far reaching energy and carbon emissions reductions, being still cost effective. The focus is to highlight advantages and innovative (but feasible) solutions and strategies., info:eu-repo/semantics/publishedVersion

Buildings are responsible for a major share of energy use and have accordingly 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. IEA-EBC project «Cost-Effective Energy and Carbon Emissions Optimization in Building Renovation» intends to develop a calculation basis for future standards, which aim at maximum effects on reducing carbon emissions and primary energy use. Thereby, the project pays special attention to the renovation of existing residential buildings and to cost effective building renovation

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.

Dissertação de mestrado integrado em Engenharia Civil, Com o passar do século XX e em virtude de um crescimento populacional exponencial a nível global, a indústria da construção no geral sofreu grandes alterações que contribuíram em enorme escala para o consumo desmedido de recursos naturais, a degradação de ecossistemas, a produção excessiva de resíduos, a poluição atmosférica e consequente degradação do planeta. Como consequência, ainda existe atualmente uma grande dependência dos combustíveis fósseis que, juntamente com as elevadas necessidades energéticas da indústria da construção, levou a uma dependência energética externa na UE. Neste contexto têm vindo a ser feitos esforços para a redução do impacto da indústria da construção na deterioração do planeta e na dependência energética externa, sendo o decréscimo do consumo e a alteração das fontes de energia utilizadas nos edifícios parte essencial da solução. Como tal, a reabilitação energética é fundamental na redução do consumo energético. É fulcral o estudo da reabilitação energética não só numa vertente de obtenção da maior rentabilidade possível, mas também no sentido de alcançar os níveis de custo ótimo de rentabilidade. A realização da presente dissertação tem como objetivo a avaliação das melhores soluções de reabilitação energética no setor da construção à luz da metodologia europeia de cálculo dos níveis ótimos de rentabilidade. O estudo é direcionado ao cálculo das soluções de custo ótimo de edifícios residenciais multifamiliares. Através da utilização da metodologia é obtida a otimização de custos, consumos energéticos e emissão de gases de efeitos de estufa para edifícios residenciais multifamiliares. Em suma, a meta a atingir com esta dissertação é a identificação dos níveis ótimos de rentabilidade do desempenho energético para alguns edifícios multifamiliares em Portugal., Over the last century and due to the exponential population growth worlwide, the construction industry has undergone major changes that contributed in large scale to the excessive consumption of natural resources, ecosystem degradation, excessive waste generation, air pollution and consequent degradation of the planet. As a result, there is currently a large dependency on fossil fuels, which together with the high demand of energy of the construction industry, led to an external energy dependency in the EU. In this context, efforts have been made to reduce the impact of the construction industry on the deterioration of the planet and external energy dependency, being the decrease in energy consumption and the change of energy sources used in the buildings an essential part of the solution. As such, energy rehabilitation is assumed as a fundamental piece for reducing energy consumption. It is crucial to study the energy rehabilitation not only as a mean of achieving higher profitability, but also in order to achieve more adequate primary energy consumption levels in response to future requirements. This work has as main purpose the evaluation of the best energy efficiency measures in construction industry obtained under the application of the European methodology for the calculation of cost optimal levels. This study used the methodology for the calculation of cost optimal solutions in residential multifamily buildings. With this methodology, the cost optimal solutions, the energy consumption and greenhouse gas emissions in multifamily building were obtained. So, the goal to achieve with this study was the identification of the cost optimal levels of profitability in the energy performance of some multifamily buildings in Portugal.

Dissertação de mestrado integrado em Engenharia Civil, Este estudo foi realizado com o intuito de analisar, a nível nacional, as medidas de melhoria da eficiência energética a implementar em edifícios unifamiliares, de forma a determinar a sua rentabilidade económica a longo prazo. Depois desta análise, procedeu-se à criação de um ranking, que facilitará a tomada de decisão quanto às medidas mais rentáveis a ser implementadas. Em primeiro lugar, foram escolhidas as zonas do país a serem estudadas, tendo em conta fatores como: zonas climáticas, zonas com maior quantidade de edificado e a procura na reabilitação de edifícios. Após a escolha das zonas/cidades a analisar, foi utilizado um edifício tipo para cada uma delas que correspondesse a uma aproximação do edificado na realidade das mesmas zonas. Foram selecionados os vários conjuntos de equipamentos de produção de energia que seriam objeto de estudo em cada zona/edifício tipo. Estes conjuntos foram então analisados comparando o edifício tipo e o mesmo edifício com a implementação de uma medida de melhoria da eficiência energética, nomeadamente: isolamentos na envolvente e mudança de envidraçados. Para tal, recorreu-se à metodologia de cálculo do Regulamento do Desempenho Energético dos Edifícios de Habitação (REH) para calcular as necessidades de energia primária, por forma a chegar aos custos energéticos decorrentes da implementação das novas medidas a longo prazo. Somando estes custos com os da implementação das medidas de melhoria mais os da manutenção, obtiveram-se todos os custos que decorrem da implementação de uma medida de melhoria, num determinado conjunto de equipamentos de produção de energia, para cada zona em estudo. Para se obter a rentabilidade económica da implementação de uma determinada medida de melhoria, fez-se a diferença entre os custos do edifício tipo com o edifício com a medida de melhoria implementada. Finalmente, após serem calculados os resultados da rentabilidade económica de todas as medidas estudadas procedeu-se à criação do ranking. Este ranking tem como objetivo, demonstrar, para as diferentes zonas estudadas, quais as medidas que produzem maior rentabilidade e são a melhor opção, do ponto de vista da rentabilidade económica, a ser executada., This study was conducted in order to analyze, at national level, the measures that can improve the energy efficiency of single-family buildings in a renovation process, and determine their long-term economic viability. After this analysis, the aim is to create a ranking that will facilitate decision making on the choice of the most cost-effective measures that can be implemented. First, it was chosen the areas of the country to be studied, taking into account factors such as zones with high urban density, climatic zones and zones with higher demand in buildings renovation. After the selection of areas / cities to be analyzed, some virtual reference buildings were built, representing the prevailing characteristics of the real buildings. Various sets of energy systems were selected, which would be the object of study in each zone / building type. These sets would then be analyzed according to a comparison between the building type and the same building with the implementation of energy efficiency improvement measures like envelope insulation or change of windows. For such, it was used the methodology of the Portuguese thermal regulation in force (REH), particularly in what concerns the calculation of the primary energy needs. These energy needs are important for the determination of energy costs resulting from the implementation of longterm measures. These costs, together with investment costs related to the improvement measures considered, and maintenance costs, were calculated for each type of building in each climatic zone analyzed and taking into account different building systems. To obtain the cost-effectiveness of the renovation measure, it was calculated the difference between the costs of a reference building and the building with the application of the renovation measure. Finally, after calculating the cost-effectiveness of all renovation measures considered in this study, a ranking of measures was created. This ranking is useful as it points out the most costeffective measures for each type of building and for each zone considered in the study.

Dissertação de mestrado em Construção e Reabilitação Sustentáveis, Atualmente, no sector dos edifícios, verifica-se um consumo de 40 % da energia total na União Europeia (EU) e com a continuação do crescimento desse sector, prevê-se um aumento do consumo de energia, sendo por isso necessário implementar medidas para a redução do consumo da mesma, aumentando a eficiência na sua utilização e utilizando fontes renováveis para reduzir a dependência energética e emissões de gases com efeitos de estufa. Neste contexto, a Diretiva Europeia 2010/31/UE de 19 de Maio de 2010 relativa ao desempenho energético dos edifícios (EPBD recast) introduz medidas importantes para a redução da dependência energética da UE e das emissões de gases com efeito de estufa. Com a EPBD Recast, os Estados-Membros deverão garantir que os requisitos mínimos de desempenho energético são assegurados com níveis de rentabilidade ótimos, ou seja, com o custo mínimo considerando todo o seu ciclo de vida. Esta dissertação pretende determinar os níveis ótimos de rentabilidade dos requisitos mínimos de desempenho energético na reabilitação de um edifício unifamiliar de referência que é representativo da construção característica da época anterior ao ano de 1960, mediante o cálculo do custo de implementação de medidas de eficiência energética, bem como do custo de utilização do edifício durante o ciclo de vida económico estimado. É avaliada a variação dos níveis ótimos de rentabilidade na reabilitação de edifícios unifamiliares nessa época, localizados em várias regiões do país com diferentes condições climáticas. É caracterizado o parque edificado em Portugal e identificadas as medidas de melhoria para a reabilitação em duas vertentes diferentes: atuando na envolvente e atuando nos equipamentos de aquecimento, arrefecimento e aquecimento de águas sanitárias. São quantificados os custos globais associados a cada uma das variantes constituídas por combinações de medidas de melhoria ao nível da envolvente opaca e com a utilização de diferentes equipamentos de climatização e AQS, para conseguir que o desempenho energético do edifício ou da sua parte renovada seja melhorado, de forma a cumprir os requisitos mínimos de desempenho energético de edifícios e alcançar os níveis ótimos de rentabilidade. Finalmente conclui-se sobre quais as variantes mais vantajosas a nível de custo/beneficio a utilizar na reabilitação de edifícios de habitação com as mesmas características do edifício de referência, típicas da construção anterior ao ano 1960 em Portugal., Currently, in the buildings sector, there is a 40% consumption of total energy in the EU and with the continued growth of this sector, there is an increase for energy consumption and it is therefore necessary to implement measures for the reduction of consumption, improving the efficiency in its use and using renewable sources to reduce energy dependency and emissions of greenhouse gases. In this way, European Directive 2010/31/EU of May 19, 2010 on the energy performance of buildings (EPBD recast) introduces important steps required to reduce EU energy dependency and emissions of greenhouse gases. With the EPBD Recast Member States shall ensure that minimum energy performance requirements are assured with good profitability levels, i.e. with minimum cost considering the entire life cycle. This thesis aims to determine the cost optimal levels of the minimum energy performance requirements in the renovation of a reference single-family building that represents the Portuguese construction before 1960, by calculating the cost of implementing energy efficiency measures, as well as the cost of using the building during the estimated economic life cycle. The variation of the cost optimal levels in the renovation of single-family buildings from the chosen period, located in various regions with different climatic conditions is evaluated. The residential building stock in Portugal is characterized and the improvement measures for renovation in are identified, including measures to improve the building envelope and also acting in the building systems for heating, cooling and domestic hot water (DHW). The overall costs associated with each of the combinations of measures to improve the energy performance of the bulding envelope and for the use of different AVAC and DHW systems is quantified, to get the energy performance of the building or the renovated part improved in order to meet minimum energy performance requirements for buildings in order to achieve cost optimal levels. Finally, it is identified the most advantageous combinations in terms of cost / benefit to use in the renovation of residential buildings with the same characteristics of the reference building, typical of pre-1960 construction in Portugal.