These buildings function like a thermos, with no thermal losses or gains in winter and summer. Furthermore, their constant ventilation improves air quality.
For the past decade, we have been hearing about passive houses, specifically Passivhaus buildings (the most widespread standard in Europe, proposed by the Passivhaus Institute of German origin, which also acts as a certifier). Up until now, the examples we have come across in Spain have been second homes or, in the case of Madrid, residential areas outside the M-30 perimeter. This week, Belén Villalvilla, a technical architect with extensive experience as a project manager, is overseeing the final steps of one of her most special projects for two reasons: it will be the first Passivhaus residence within the metropolitan area of the M-30, and it will be her own home. Alongside her partner Jaime, an engineer by profession, she acquired a plot in Madrid’s Barrio del Pilar five years ago. After a year of research on this type of house and visiting some of them, they decided that this was what they wanted for their dream home.
The Pilar Passivhaus is now a reality; they named it as a triple tribute to the family’s origins in Zaragoza, their profession, and the neighborhood where it is located.
WAR ON THERMAL BRIDGES
Choosing to build a passive house requires a greater initial effort for the developer (in this case, this self-building couple), but the advantages more than compensate for it: almost zero energy consumption, excellent air quality, and comfortable temperatures in winter and summer. “Pre-planning is more necessary than in other types of construction,” explains Villalvilla, adding, “A closed and defined project is needed from the beginning so that no element that affects, for example, the elimination of thermal bridges, one of the hallmarks of these constructions, is modified during execution.” Through an airtightness membrane, the building functions like a thermos, with no energy losses, but it requires constant ventilation.
In the case of this residence, this is achieved through a mechanical ventilation system with heat recovery powered by a Canadian well (a geothermal energy system that brings warm air into the house in winter and fresh air in summer, taking advantage of the natural temperature of the ground. It is a renewable energy source with very low implementation and maintenance costs. The little supplementary energy required can also be covered by renewable energy sources, which has also been done in this home, where eight photovoltaic panels have been installed, providing up to 3.2 kW and practically covering the electrical consumption of the residence. “Despite our technical knowledge, we have done a lot of research,” comments the homeowner, who suggests that it is necessary to work with a professional for such a project, for which they took almost two years to obtain the construction permit. “These houses are still hidden gems in Spanish architecture, and there is quite a lack of awareness,” she asserts.
Last week, the final blower door test was conducted, using a machine to measure the airtightness of buildings. The result validates the Passivhaus criteria with a value of 0.50 air changes per hour in the residence (the maximum value for a certified residence is 0.60 ACH, while it is not uncommon to find values of 5 ACH in a typical home). During the construction phase, it was observed that there was barely a two-degree variation between day and night inside the residence. This was one of the first indications that the system was working in practice and not just on paper.
A HOME THAT WILL SERVE AS A PASSIVHAUS GATHERING POINT
This family’s residence has three floors with multifunctional spaces where directed light predominates, creating a sensation of absolute brightness that, however, does not compromise comfort or visual appeal. The lower floor features a spacious 30-square-meter open area with its own patio, which will serve as the owner’s professional office, as well as a space for training and events related to this type of construction. After five years of research in this field and having successfully certified their house as a Passivhaus, this architect is willing to support other future homeowners who want to follow in their footsteps. “To have an appealing residence, you must devote time to each space and envision how you want to live in it. Then, a professional will guide you through the steps and help shape it,” Villavilla suggests. Each passive house will have its own unique characteristics, as it does not require the use of specific materials or styles, but rather the maximum optimization of existing resources, orientation, and insulation in the construction process.
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