Non-residential and more specifically office buildings are, nowadays, an integral part of the building stock and milestones of urban areas in most of the developed and developing countries all over the world. Compared to other building types, office buildings present some of the highest specific energy consumption rates. In the present study, a typical nine-story office is assessed for a number of different building integrated retrofitting measures. Measurements of indoor environmental conditions were used in order to validate the developed simulation model of the building in EnergyPlus. Then, a number of different building integration options for photovoltaic systems and shading options are examined, in order to evaluate the best option in terms of indoor air quality, thermal comfort and energy consumption. The amount of electricity produced can meet 65% of the building’s annual electricity requirements, while the shading options can reduce energy requirements by as much as 33%. Although this in not a value that can be dismissed easily, it becomes clear that further—and more deeply aiming—measures are needed, if the building is to achieve near zero energy status.

Pursuing high energy performance with the least environmental impact of a building, along with ensuring the well-being of the occupants, is the ultimate goal of an institutional framework that addresses energy efficiency and environmental sustainability. The building sector is responsible for 38% of the total final energy consumption in Europe and is therefore in the epicentre of the effort to achieve improvements. This is being expressed by the targets of EU policies for 2030 and 2050, which set truly ambitious goals. Part of this effort is the improvement of the building’s envelope thermal performance, along with the respective one of the HVAC systems, but also integrating those two in the best possible way. The façade is the crucial factor, as it is the interface between the building and its environment, but also between the environment and the HVAC system; it is truly the building’s skin, which is therefore much more than a simple state boundary, if we want to have truly advanced buildings. Main scope of the paper is to present the results of an in depth investigation regarding the best available technologies and the upcoming trends of intelligent building façades, to be used in Zero and Positive Energy Buildings. This cannot be done without discussing the legislative and regulatory framework that applies for the building envelope, as solutions have to comply with regulations and standards, both national and international. In this line of approach an investigation of the practices and technical approaches best suited for Greece is being made, specifying their performance, possible drawbacks and approaches that are to be applied and the implementation of which is expected to contribute to the improvement of the buildings’ performance. Furthermore, the constructional approaches and the effectiveness of both naturally and mechanically ventilated façades are discussed, along with their adaptation to the Greek building practices. The integration of ventilated façades with the building’s HVAC systems may offer advantages, especially in spring and fall when preheating the air may lead to reduced energy requirements. In the opposite direction, heat rejection may be a problem in summer, where alternative cooling techniques can provide a solution. Finally, integration of innovative design elements such as the use of different final coating materials on the façades, the use of phase-changing materials (PCMs) and the integration of photovoltaic systems are evaluated.

Despite the significant progress observed over the last decades, the European building stock still consumes significant amounts of energy (39% of the total final energy), whilst it does not always provide the conditions required for occupants’ well-being and thermal comfort sensation. In order to achieve the goal of nearly or even zero energy buildings, a deep refurbishment of the building stock is imperative. As the literature indicates, a firm evaluation of indoor conditions is essential, while having at the epicenter the occupants’ comfort perception, with emphasis on their individual characteristics. In this respect, a methodological framework is developed and a preliminary implementation is performed. The main goal of the methodological approach is the consideration of both the classical comfort parameters along with the occupants’ socioeconomic and personalized characteristics that affect their perception and can differentiate their needs even under the same conditions. Among other important findings this preliminary implementation achieved some very promising results, highlighting that occupants’ individual characteristics such as recycling and exercising can affect the occupants’ comfort perception.

The purpose of this study is to shade light in the field of buildings thermal comfort under subtropical environmental conditions. For this purpose, a survey and a measurement campaign of the thermal comfort conditions in 30 dwellings in Larnaca, Cyprus, was conducted. The results showed that 75% of the tenants fall within the warm and the hot thermal sensation category, whereas most of the respondents considered the thermal conditions in the investigated dwellings as neutral or close to neutral. Based on the information gathered in the field survey, interesting conclusions were drawn concerning the actual prevailing indoor conditions, but also the clothing habits of the people interviewed.

Environmental aspects are of high priority for the identification and evaluation of the parameters that affect the design and construction of buildings. Their improvement in case of the existing European building stock while considering and maintaining the occupants' comfort sensation in high levels, is imperative for creating an environmental friendly building. The combination of those aspects can upgrade the indoor conditions leading to the creation ofan appealing workspace where the well fair of the occupants is established. In this line of approach, an integrated evaluation of the indoor environmental parameters was conducted in office buildings, located in Thessaloniki, Greece, based on the occupants' comfort sensation. Main goal of the study is the determination of the existing correlations between the perceived comfort sensation and a variety of environmental parameters considered in building rating certification schemes. Those correlations can outline the weight of every aspect based on the occupants' view and also help the policy makers to accomplish the vision of an environmental sustainable, not only concerning the energy consumption but also the occupants, building.

Heading towards sustainability and nearly zero energy buildings (nZEBs), the main obstacle that needs to be overcome is the energy consumption of the existing building stock accounting for 40% of the global energy consumption. Therefore, the main target of the European Union is the reduction of the buildings’ energy consumption, achieved by efficient and clean energy consumption for heating and cooling as well as by designing smarter buildings, with improved appliances and insulation materials. In this line of approach, new construction typologies are being developed focusing on decreased energy consumption. As part of the IF-ZEB research project, a family of intelligent facades are being established, based on innovative coating materials and the integration of ventilated facades in existing and new buildings, towards the vision of nZEBs. Scope of this paper is the detailed presentation of the constructed ventilated facades with innovative final coating materials along with their implementation to the Conservatory of Thessaloniki.