The ‘Passiv Haus’ has been developed over a decade ago by Dr Wolfgang Feist of the Passivhaus Institut in Germany.

Passive House is a building standard that is truly energy efficient, comfortable and affordable at the same time.

Passive House is not a brand name, but a tried and true construction concept that can be applied to any design, anywhere.

Yet, a Passive House is more than just a low-energy building:

  • Passive Houses allow for energy savings of up to 90% compared with a conventional build. Passive Houses use less than 1.5m3 of gas to heat 1sqm of living space for a year – substantially less than common “low-energy” buildings. Vast energy savings have been demonstrated in warm climates where typical buildings also require active cooling.

  • Passive Houses make efficient use of the sun, internal heat sources and heat recovery, rendering conventional heating systems unnecessary throughout even the coldest of winters. During summer months, Passive Houses make use of passive cooling techniques such as strategic shading to keep comfortably cool.

  • Passive Houses are praised for the high level of comfort they offer. Internal surface temperatures vary little from indoor air temperatures, even in the face of extreme outdoor temperatures. Certified windows and a building envelope consisting of a highly insulated roof and floor slab as well as highly insulated exterior walls keep the desired warmth in the house – or undesirable heat out.

  • A ventilation system imperceptibly supplies constant fresh air, making for superior air quality without unpleasant draughts. A highly efficient energy recovery unit allows for the energy contained in the exhaust air to be re-used.

Carbonlite design+build specialises in meeting the very strict requirements of the Passive House below:


Thermal Insulation: All opaque building components of the exterior envelope of the house are so well-insulated that they have a heat transfer coefficient (U-value) of 0.15 W/(m²K) at the most, i.e. a maximum of 0.15 watts per degree of temperature difference and per square metre of exterior surface are lost.

Triple Glazed Windows: The windows should not exceed a U-value of 0.80 W/(m²K), with g-values around 50% (g-value= total solar transmittance, proportion of the solar energy available for the room).

Energy Recovery Ventilation: This system with highly effective energy recovery firstly allows for a good quality of indoor air, and secondly it helps to save energy. In the Passive House, at least 75% of the energy from the exhaust air is transferred to the fresh air again by means of a energy exchanger. Fresh air is also filtered from pollen and dust before distributed into the house.

Air Tightness of the Building: Uncontrolled leakage through gaps must be smaller than 0.6 of the total house volume per hour during a test with a negative pressure/excess pressure of 50 Pascal. This will be tested with a ‘blower door test’ after installation of the airtight membrane.

Elimination of Thermal Bridges: All edges, corners, connections and penetrations must be planned and executed with great care, so that thermal bridges can be avoided. Thermal bridges which cannot be avoided must be minimised as far as possible.

Learn more about Passivhaus; Click here