The goal of this study is to characterize the thermal performance of the opaque ventilated facade from sample-scale to building scale. To begin with, a representative sample has been built in order to test it in outdoor conditions using a traceable and precise methodology. The testing equipment used is a PASLINK test cell developed by DYNASTEE network at the Basque Government Laboratory of Quality Control in Buildings.The experimental results provide information to define a mathematical model of the ventilated gap's convective behavior for the application of building scale simulation. In this way, a building dynamic simulation has been carried out by TRNSYS. Results not only show the benefits of this solution in warm climate areas and drawbacks in cold climate areas, but also provide guides for the optimization and improvement of the opaque ventilated facade

A study of moisture pathologies in a modern residential multifamily building is presented. The housing block was designed under the regulation NBE-CT of 1979 in northern Spain. After the appearance of some moisture problems in the façades, three complementary studies were conducted to analyze the situation of the envelope and diagnose the best improvement possibilities. First, indoor conditions of temperature and humidity of the apartments with moisture pathologies were monitored. During 40 winter days, the occupancy, heating operation, and natural ventilation were analyzed. Second, the inner and outer surface temperatures of the studied façades were measured. Thermal insulation degree, thermal capacity, and thermal bridge effects were measured to assess the risk of interstitial condensation under the real conditions of use. Third, an infrared thermographic survey was carried out, which allowed the detection of irregularities and the assessment of moisture problems. The wrong interpretations, which would have been made if the complementary studies had not been done, are exposed. The key towards the accurate diagnosis was the combination of tools. Finally, some technical solutions based on ventilation or thermal insulation enhancement are proposed as different ways to reduce the high levels of relative humidity indoors and minimize the risk of condensation in the future.

The requirement of a minimum air flow rates in dwellings is new in the Spanish regulation. The value of the minimum air flow rate for each room of the dwelling depends on the type of room, its occupation or its dimensions. To achieve these air flow rates, in the houses built in the Basque Country, mechanical ventilation systems are installed, usually: simple flow with continuous extraction, hygrorregulated simple flow or double flow with heat recovery ventilation systems.The permeability of the envelope is a very important parameter, that must be cared for the correct performance of the ventilation system installed. This performance must be measured in terms of energy consumption, but also in terms of indoor air quality, because the objective of the ventilation system is to ensure an adequate indoor air quality.It has been analyzed the quality of indoor air and the energy consumption of a dwelling for the three systems of ventilation, and for three levels of permeability. The analysis of the indoor air quality has been done checking 15 contaminants. As conclusion, we can say that in the case of the two simple flow ventilation systems, the permeability affect mainly on the indoor air quality, but in the case of the double flow with heat recovery ventilation systems on the energy consumption