Passive House Design

Air tightness is defined as preventing the flow of unplanned air entering a building through gaps and cracks in the building fabric which leads to an energy efficient, affordable, eco-friendly construction.

An air-tight membrane is installed on the inside of building envelope; this inner barrier protects the interior of the building against infiltration of outside air. Insulation prevents the escape of heat from the inside. Uncontrolled air leakage of a dwelling can cause sudden changes in building temperatures thus leading to discomfort of the occupants. In windy or stormy conditions the infiltration of air will increase, making it difficult to adequately heat the dwelling, consequently the building’s demand for heating energy increases. As a result of uncontrolled infiltration of air through gaps or crack in the fabric of the building. There are also local drafts which apart from cooling rooms, disturbs the comfort of the residents.

Air leakage of warm damp air through the building structure can also lead to condensation within the fabric (interstitial condensation), which reduces insulation performance and causes fabric deterioration.

Why is it important to maintain air tightness of a building?

  • Less energy loss. The leak-proof coating on the inner side of the building prevents heat loss due to the penetration of cold air into the interior. Comparing with typical building – Passive House allow for up to 90% energy savings.
  • Thermal comfort of the interior. It results from the ability to maintain constant interior temperature and stable air velocity. Sealed coating prevents uncontrolled air movement.
  • Healthy microclimate of the interior. Air tightness prevents infiltration of the external pollutants, pollen and toxic substances, e.g. contained in exhaust gases or wood preservatives to the interior.
  • Building durability. Leaks cause damage as a result of condensation of water vapour. The warm air leaking through the leaks condenses in the partition material. Condensation of moisture can lead to the destruction of building elements, such as roof and consequently, to the weakening of the whole structure.
  • Sustainability – Passive Houses are sustainable.
  • Affordability. Are Passive Houses a good investment? Passive Houses not only save money over the long term, but are surprisingly affordable to begin with. The investment in higher quality building components required by the Passive House standard is mitigated by the elimination of expensive heating and cooling systems. Additional financial support increasingly available in many countries makes building a Passive House all the more feasible.

You can check our range of quality airtightness materials HERE.

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