The term Passivhaus comes from the German expression “Passive House”. It was in the 1980s that this concept was developed and it has led to a standard for low energy housing construction, that is more current than ever.
The history of the Passivhaus standard
In 1988, Professors Wolfgang Feist of the Institute for Building and Environment in Germany and Bo Adamson of Lund University in Sweden created this model and coined the term Passivhaus.
In 1990, the first building that aligned with their principles was built in Darmstadt, Germany and there, some time later, in September 1996 the Passivhaus-Institut was founded. This not only extended the system, but also controlled the standard. In the same year, the Economical Passive Houses Working Group was also established. Later on, Passivhaus houses were built mainly in Germany and Austria, extending to the rest of Europe and reaching the USA in 2003, with the construction of the first building under the Passivhaus standard in Urbana (Illinois) and the first one certified in Waldsee (Minnesota) in 2006.
To achieve a reduction of up to 90% in the energy demand for heating which was the premise of the passive house, it was necessary to technically develop highly energy-efficient ventilation and glazing systems.
How does a Passivhaus works?
The goal of passive houses is to achieve between 70% and 90% of energy savings compared to a conventional house. To achieve this, it is essential to work comprehensively from the design phase of the project. Then, among other things, the most appropriate orientation is defined, which will be essential for the energy consumption of the house. In addition to this, there is a necessity to have thermal insulation of the enclosure, the breaking of thermal bridges, high-performance doors and windows, mechanical ventilation with heat recovery and the use of internal heat sources.
All of this is done with the aim of guaranteeing the water-tightness of the building, completely eliminating air infiltration and minimizing energy consumption. In these tasks, polyurethane plays a leading role due to its low thermal conductivity and its sealing capacity. It provides a continuous layer, without joints or gaps that facilitate the necessary tightness.
The Passivhaus standardization system has been extended, so that certifications are already issued by various entities, such as the International Passive House Association (IPHA), Effinergie, Minergie or Effizienzhaus Plus.
In order to obtain recognition of the certification, there are minimum requirements that must be met, which are thermal insulation, air quality, solar energy use and sealing conditions. This requires the evaluation, management and supervision of a Passivhaus technician, who will take these five general criteria into account:
- Heating costs: less than 15 kWh/(m2a)
- The cost of cooling: less than 15 kWh/(m2a).
- Primary energy consumption: less than 120 kWh/(m2a) for heating, hot water and electricity.
- Airtightness: less than 0.6 air renewals per hour (value with a pressure differential of 50 Pa.
- Thermal comfort.
The correct temperature and good air quality are fundamental in a passive house, so this type of construction is not only sustainable but also healthy for its users.