The Passivhaus standard has traditionally been developed in cold climates but for some time now it has been extended to areas with warmer temperatures. The high incidence of heat in summer and the evolution of the climate in all latitudes mean that bioclimatic architecture is on the rise and techniques and materials capable of keeping homes cool in summer and warm in winter with low energy consumption are being applied. In Spain, it is currently enjoying a moment of great expansion, supported by numerous projects and events. Meetings such as the Spanish Passivhaus Conference, now in its 16th edition, specialized architectural studios and materials specially designed for the building standard confirm this trend.  In recent years, multi-family houses, schools, cultural spaces, office buildings and conference centers in Spain have achieved Passivhaus certification. All over the country, building is progressing steadily and there are many designers who trust Ytong to carry out this type of project. Ytong plays a key role in low- or zero-energy projects, with Xella Spain supplying innovative materials for both single- and multi-family homes and having recently launched a new ventilated façade system for multi-family homes, designed to meet Passivhaus standards together with URSA.

New Ytong enclosure system for passive houses

The YTONG - URSA External Wall Ventilated Façade System is an enclosure system specially designed for multi-family houses that guarantees a continuous envelope with high insulation values. The cladding can be adapted to the needs of the designer and different solutions to ensure the airtightness, both on the inside face of the walls and those susceptible to movement, as well as in the joints with the exterior carpentry and installation passages.

In order to comply with the Passivhaus standard, it is crucial to guarantee the correct performance in critical areas. "The great contribution of this cladding system is that in addition to working in terms of thermal insulation and airtightness, it addresses one of the fundamental goals of low-energy houses, the thorough elimination of thermal bridges, without detriment to the final aesthetics of the façade" says Cristina Tomás, technical manager of Xella Spain for the Levante area and main developer of the cladding system for ventilated façades.
 
As Pablo Rodríguez, Head of national technical department of Xella Spain points out, "to achieve the certification, every project must follow strict guidelines, from design and planning to final validation by the Passive House Institute. The project must be developed by professionals, familiar with the principles, using tools such as the Passive House Planning Package to model and forecast the building's energy performance. During construction, it is essential to maintain high quality standards to ensure that the criteria for airtightness, insulation and other passive house principles are met. Tests such as the Blower Door Test are carried out to verify that the building complies with airtightness requirements, and finally an accredited certifier evaluates all documentation and test results. If the building meets all criteria, certification is awarded.

Mediterranean comfort in Ca la Siesta

Ca la Siesta, a single-family house in Jávea by Bataille Living, showcases the adaptability of low-energy house design to diverse climates and styles. With a combination of Ytong structural and partition walls and other products, Ca la Siesta achieved Passivhaus certification and was presented at the 15th Spanish Passivhaus Conference organized by the Passivhaus Building Platform. According to Enrique Salavert, the project's technical architect, "the aim was to build a Mediterranean-style house with special emphasis on the sustainability of the house, which is why materials such as Ytong, natural cork insulation in floors and wood fiber insulation were chosen". The house has a low water footprint thanks to the collection of water from all roofs and terraces and a grey water reuse system. A project with a photovoltaic system, controlled ventilation and a high level of comfort thanks to the thermal and acoustic insulation characteristics of the Ytong, whose envelope "as well as all the interior partition walls offer great thermal properties, something highly valued in our hot climate," says Salavert.

Further project in Valencia

A project underway for future Passivhaus certification is being led in Valencia by the Lasar architecture studio, which was recently visited by managers from Xella North West Europe. A 250 m2 house designed under bioclimatic criteria and passive measures for solar and temperature control, with overhangs that will allow optimal use of solar energy in winter and summer. The Ytong blocks and the exterior insulation of Multipor guarantee a high degree of thermal and acoustic insulation reducing the environmental impact of the project, offering its owners a comfortable and healthy home free of toxic materials and VOCs.