Passive House

Passive House (Passivhaus)

Passive House (originally Passivhaus in German) is a rigorous, voluntary standard for energy efficiency in buildings. It reduces a building’s ecological footprint while maintaining exceptional indoor comfort. Passive House buildings consume very little energy for heating or cooling, making them one of the most sustainable approaches to modern construction.

Origin

The concept was developed in the late 1980s by Dr. Wolfgang Feist of the Passive House Institute (PHI) in Darmstadt, Germany, in collaboration with Professor Bo Adamson from Lund University in Sweden. The first experimental Passive House was built in Darmstadt-Kranichstein in 1991 and has since influenced building design worldwide.

Key Principles

A Passive House relies on several design and engineering strategies to achieve ultra-low energy demand:

  1. Superinsulation

    • Walls, roofs, and floors have very high insulation levels to minimize heat loss.

  2. Airtightness

    • The building envelope is constructed to be almost completely airtight, preventing uncontrolled airflow.

  3. High-performance windows and doors

    • Triple-glazed, low-emissivity windows and insulated frames are used to reduce heat transfer.

  4. Thermal bridge-free design

    • Construction details eliminate or minimize areas where heat could easily escape.

  5. Heat recovery ventilation (HRV)

    • Mechanical ventilation systems with heat exchangers recycle warmth from outgoing stale air to incoming fresh air.

Energy Efficiency Criteria

For a building to be certified as a Passive House by PHI, it must meet strict criteria, including:

  • Annual heating and cooling demand ≤ 15 kWh/m² per year.

  • Primary energy demand (including household electricity) ≤ 120 kWh/m² per year.

  • Airtightness: ≤ 0.6 air changes per hour at 50 Pascals pressure (tested with a blower door).

Benefits

  • Energy savings: Up to 90% less energy for heating and cooling compared to conventional buildings.

  • Comfort: Stable indoor temperatures, no drafts, and balanced humidity.

  • Health: Constant fresh air through HRV systems reduces indoor pollutants and allergens.

  • Sustainability: Lower carbon footprint due to reduced reliance on fossil fuels.

  • Cost-effectiveness: Higher initial investment, but lower operating costs and long-term savings.

Applications

Passive House principles can be applied to:

  • Residential homes (single-family, apartments)

  • Office buildings

  • Schools and kindergartens

  • Hospitals and public facilities

  • Retrofits (with EnerPHit, a Passive House standard for renovations)

Global Spread

Since its origin in Germany, Passive House has spread globally. Many countries now have Passive ragdoll hit House associations, and adaptations exist for different climates (cold, hot, humid). The concept is increasingly used in sustainable urban planning and large-scale developments.

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