Metathesis member of the Passive House Association.


Passive House is not an energy standard, but an integrated concept ensuring the highest level of comfort. The exact definition is as follows:

"Passive House is a building whose thermal comfort (ISO 7730) can be achieved only by postheating or aftercooling of fresh air mass, which is necessary to achieve sufficient indoor air quality conditions – without the need for additional air recirculation."

This is a purely functional definition that does not contain numeric values and is valid for all climates. The Passive House concept was not "invented" by anyone – in fact, the principle of Passive House was discovered. Thermal comfort is achieved through passive measures (insulation, heat recovery, passive use of solar energy and internal heat sources).

The following considerations help you better understand this concept:

  • All airtight buildings (any low-energy building needs to be airtight), except those in so-called moderate climates, require the use of an efficient ventilation system. In Passive Houses this system can also be used for heating purposes, without the need for additional systems, main technical interfaces, auxiliary fans etc.
  • This concept allows the construction of houses equipped with a highly efficient heat recovery system at a very affordable price which is usually difficult to do, since the ventilation system costs as much as a heating system – a investment that for a couple hardly pays off. As such, it is chosen to cut into one of the two systems: or in the ventilation system, installing only one exhaust system (in this case, the building will become a low-energy house with conventional heating) or in the heating system using the system of ventilation to heat up too – in this case, the building will become a Passive House.


This heating concept automatically implies extremely low energy consumption.

We must not forget an excellent insulation of the surrounding building – especially in cold climates to keep the desired heat inside the building, but also in warm climates to keep the undesirable heat out of it.

The calculation of the energy balance will help determine the level of insulation that will be required in a given building and climate.

Protocol Secondary School Dr. José Afonso

Protocol with the Secondary School Dr. José Afonso

Metathesis established a protocol with dr. José Afonso High School.

Under this partnership the company will welcome students from the professional courses of 11th Year and 12th Year.

The objective is to receive students and allow them to complement their training with a curricular internship in the company.

Metathesis is teamed with this Seixal County Reference School in a professional training partnership in the company thus helping in the teaching of these young people.

The first students were Carolina Rodrigues, Francisco Barata and Diogo Pereira are students of the technical professional course of management and programming of computer systems that are ending their 12th year.

This stage allows them to complete the course as it is evaluated like any other discipline.

During the internship, students perform numerous activities including documentary management, computer assistance to the company, support in management tasks, telephone service, and in a number of other projects.

The company's policy is to integrate students as if they were company employees to enable them to learn faster.

"It is a pleasure to welcome these young people. They bring "new blood" to our organization. They throw us daily challenges. They approach the future generation of customers and teach us what their needs and desires are. This also allows us to tailor our products to these needs." says the Ceo of isabel dias rodrigues

Students also participate in all events where the company is an organizer or co-organizer. They thus learn another very important aspect of the day-to-day business that is the connection to other entrepreneurs, institutions or associations.

"At Metathesis the internship is a true stage of knowledge and putting into practice of what students learned in school. They wash from here an experience very close to what the world of work is.", she says.