Passivhaus: Efficiency and sustainability in your home
Surely there are many who have heard of Passive Houses, a concept that in recent years has generated a growing interest in the real estate sector and the world of architecture in general. Well, we bring you this post in which we try to delve a little more into the meaning and characteristics of this most interesting, and for us increasingly necessary, building model.
The Passive House Standard (Passivhaus in German) was originated in 1988 by Professors Bo Adamson of Lund University of Sweden and Wolfgang Feist of the Institut für Wohnen und Umwelt (Institute of Building and Environment). The first building built with the Passivhaus standard was located in Darmstadt, Germany in 1990, constituting an astounding evolution of low energy houses. Later, in September 1996, the Passivhaus-Institut was founded with the aim of promoting and controlling the Standard to create the Economical Working Group Passive Houses Working Group.
So, while “Passive House” is a building concept appropriate to the climate that saves energy and takes advantage of site conditions, the “Standard Passivehouse” is a certification system to obtain buildings with very low energy demand for proper operation.
The main characteristic and virtue of the Passive House model is that it makes the presence of active heating systems practically unnecessary, since it is mainly derived from the heat of the sun, generated by the occupants of the house and the domestic devices, recovered from waste air. How is this possible ?, you will ask. Mainly due to “passive” components, such as windows with thermal insulation, heat exchange systems and efficient insulation.
Passive solar systems are used to a large extent to capture and accumulate heat from solar energy. They are called passive because other electromechanical devices are not used to recirculate the heat. This is due to basic physical principles such as conduction, radiation and convection of heat. We can therefore say that in a Passive House the thermal comfort is due in large part to the use of the passive measures listed below, not only applicable in the residential area, but also in commercial, industrial and public buildings:
- Adequate levels of insulation, with minimum thermal bridges
- Passive solar gain and internal heat sources
- Excellent watertightness
- Optimum indoor air quality thanks to a highly effective mechanical ventilation system with heat recovery (MVHR) for the whole house
At this point, we will have realized that the concept of Passive House has been a major evolution of low-energy houses, having already built thousands of homes with this standard, many of which are located in Germany and Austria. Due to the excellent thermal quality of the materials used to close the building (walls, windows and doors), the use of internal heat sources (from electrical devices normally used in homes) and the Minimizing ventilation losses with a controlled system with heat recovery, passive housing makes conventional cooling or heating mechanisms unnecessary. This has only been possible since the development of ventilation and glazing systems of high energy efficiency.
Thus, a dwelling that meets this standard is expected to produce a heating demand of less than 15 kWh / m2, which translates into a 90% reduction in demand for that energy. As we see, the need for heating in a Passive House is reduced to the point that a traditional heating system is no longer considered essential. On the other hand, cooling is also minimized by applying the same principles and by using shadows, as well as, in certain cases, by pre-cooling the air supply.
We should not confuse the Passivhaus or Passive House standard with more generic approaches to passive solar architecture, with which, it is true, shares some common principles. What really sets Passive House apart from other generic concepts is its ability to reduce maximum heating demand for space and primary energy consumption. For this reason, an advanced specification of energy performance and an integrated design concept of low energy consumption can be considered at the same time.
And what happens to those existing buildings that have not been originally executed under this Standard ?, you will ask. Well we will say that it is also possible to adapt the rehabilitation of an existing building to the Passive House standard with its version for rehabilitation, known as EnerPHit. The demands are somewhat lower but the results are optimized to get the best out of the homes and make them truly efficient, comfortable and healthy.
We must not forget that energy is a scarce commodity, besides expensive. In Spain we have to import it for the most part, which makes us dependent on third countries. Reducing the energy demand of our buildings to the maximum will allow us to protect ourselves from the constant increase of its price, with the consequent saving in our economy.
In addition, the guidelines coming from the European Union increasingly establishing a greater requirement to reduce CO2 emissions. Improving the envelope of a building allows the renunciation of conventional heating / cooling systems: the energy supply needed for a home can be achieved by a pair of low-power radiators; The rest is provided by the sun, people, lighting and appliances.
As an objective data, we can say that a building rehabilitated with these approaches can recover the initial investment in less than 10 years: the slight extra cost involved is returned in that time by the drastic reduction of energy bills and maintenance costs.
At MISTRAL we are concerned about these issues because our spaces must coexist in an efficient and sustainable framework. This ideal is part of our corporate philosophy.
If you want to expand the information about the Passivhaus standard, you should know that in Spain there is the Passivhaus Building Platform (PEP), with headquarters in Madrid. It is a non-profit association that promotes the passive buildings of Spain through its delegations. It is part of the International Passive House Association and EuroPHit. PEP is financed through partners, European projects and sponsorships, its main purpose being to provide diffusion and training to technicians and professionals in the construction sector through the holding of training events throughout the national territory.