Majorca Property News

Passive houses are no exotic

Living without a conventional heating - that are passive houses. Constructionpionier Wolfgang Feist declared in an interview how the energy savings offsets the high initial investment will be.

Built 17 years ago the physicist Wolfgang Feist, the first German Passive House in Darmstadt-Kranichstein. Meanwhile satisfy nationwide 10 000 building to the strict energy standard: they consume a maximum of 15 kilowatt hours per square meter per year to heat - conventional buildings average 100 kilowatt-hours. At the "International day of the passive" of 7 until 9 November, several hundred over the whole federal territory distributed passive houses open to visitors.

FOCUS Online spoke with Wolfgang Feist, since 2008 the Engineers at the University of Innsbruck's train, on passive houses as a compromise between cost and efficiency and the general skepticism about the houses, mainly by solar radiation, body heat and heat-heating devices.

FOCUS Online: low energy, zero energy house, KfW-60-house and passive - the plethora of standards and terms for energy-saving building is enormous. What exactly differentiates a Passivhaus from all the others?

Wolfgang Feist: The Passive House standard was mainly because all of these standards. It is the result of a search for an economically reasonable level for most energy-efficient construction. The starting point was the zero-energy house, which no heat energy consumed and therefore no heating needs. Technically, it's already possible, but still does not make sense economically. The passive house is just far enough that I have to install a conventional heating system can do.

FOCUS Online: You have in 1991 in Darmstadt District Kranichstein the first passive house built in Germany. Has the multifamily everyday test?

Feist: All families who are then fed, still live in it. The disappointment for me in this project was that everyone quickly said that it was anything but normal. The limit above which I am investing in a conventional heating can save, is located in Germany at 15 kilowatt hours of heat energy needed per square meter per year. The house in Kranichstein consumes even less: This varies depending on the hardness of the winter of eight to twelve kilowatt hours. All four housing units provides a Gasbrennwertgerät with 12 kilowatts of power.

FOCUS Online: View passive houses fundamentally different than houses of traditional construction?

Feist: There are no special Passivhaus architecture. The previously completed projects is also to recognize that the single family to multi-dwelling house all types of passive houses can be. They are in our latitudes and climatic conditions throughout construction - throughout Germany.


FOCUS Online: It was founded by you Passivhaus Institute organized this weekend for the fifth time the "International Day of passive." What is it you?

Feist: Above all, as many people as possible to show that passive houses are not exotic but ordinary residential buildings, which also consume very little energy. On the other hand, passive houses are open to many visitors who will then also equal to inquire after the temperature in the house and after the consumption values.

FOCUS Online: In no other European country are there so many passive houses as in Germany. Around 10 000 should be, but still little seems. Why does the idea Passivhaus slowly through?

Feist: It remains a skepticism about passive houses, as new ideas entgegenschlägt. That is why we organize these visits. Moreover, the construction of medium-sized strongly influenced - not all companies can already produce passive houses. Passive houses have some free of thermal bridges and the whole building especially airtight. The necessary knowledge, for example, we distribute to the university.

FOCUS Online: with the rise of the great density of passive houses do not even risk the mold?

Feist: no. The main reason is the increased insulation of the walls. Thus they are at the surface so warm that no condensation forms. Even the windows are not passive in so cold that water condenses. Condensate can you actually completely forgotten.

FOCUS Online: passive houses will be mechanically ventilated, and - means that it continually attracts them?

Feist: no. Only if you hand to hold a ventilation valve, you can feel the airflow. That is just as much as you need to breathe fresh air.

FOCUS Online: In building such as the German energy saving regulation is Passivhaus standard is not mentioned. Is this a problem, such as a dispute between builders and architects?

Feist: There is no statutory standard, but a clear directive to Passivhaus standard of our institute. Experience has shown that courts in these disputes also used.

FOCUS Online: The Information Community Passivhaus quantified the incremental construction of passive houses in five to ten percent. Power of the lower energy costs competitive again?

Feist: Yes, together with the available funding in Germany credit for energy-saving construction. Their interest rate is around one percentage point below the normal market level. When Passive-building one, you have the higher investment costs and therefore pay more in total loan interest. But from the first year you feel the heat savings. Assuming both components together, the cuts from Passivhaus favorable.

FOCUS Online: How do passive houses in the maintenance costs?

Feist: In this area there is still little experience. The apartment building in Darmstadt is now 17 years old. There were the maintenance costs until now zero. Since the Gasbrennwertgerät every four dwelling units provided, the maintenance costs lower than if each apartment in a separate heating system would work. For the thermal insulation and insulated windows, no maintenance costs.

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