What does passive house mean? The five pillars Passivhaus


Emma Potter

The concept of passive house it is relatively new and the definition is not regulated; for this reason too, a thought like this arouses distrust in many: “then in winter we are the ones who chatter, not you, engineer”.

Let's first try to clarify what a passive house is. A passive house is a constructed or renovated building according to the criteria of international Passivhaus standard. The standard was born in May 1988 from a collaboration between Bo Adamson of theLund University in Sweden e Wolfgang Feist of theInstitut für Umwelt und Wohnen (Institute for the Environment and Building) in Germany.

The definition of passive house

Following the implementation of some pilot projects, the was founded in 1996 in Darmstadt Passive House Institutewhich aims to promote the standard and monitor its application.

According to definition of passive house provided by Prof. Dr. Wolfgang Feist (Chair of low-energy construction and building physics at the University of Innsbruck and director and founder of the Passivhaus Institut in Darmstadt):

“The heat losses of the building are reduced to such an extent that almost an active heating system is not even necessary. Passive heating contributions such as the sun, tenants, appliances and heat recovered from exhausted air cover a large part of the heating requirement. The remaining heat can be supplied via fresh air if the maximum heat load for heating is less than 10 W per square meter of usable surface area. If the heat input of the supply air constitutes thesingle source of heat of the building, the building it can be defined as Passivhaus”.

The five pillars Passivhaus

It is worth underlining that the Passivhaus standard it does not refer to a specific construction type, but is based on compliance with performance requirements; these requirements are related to: the thermal needs for winter and summer air conditioning, the air tightness of the building envelope, thermo-hygrometric comfort, the need for renewable primary energy for air conditioning services, production of domestic hot water, lighting and power engine.

THE pillars on which the achievement of the performances required by the standard is based five:

  • thermal insulation of the opaque and transparent building envelope,
  • transmission of solar radiation incident on the transparent casing,
  • minimization of thermal bridges,
  • airtightness of the building envelope,
  • mechanical ventilation with heat recovery.