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Passive House

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Passive House (German: Passivhaus) is an internationally recognised, performance-based energy standard in construction originating in Germany.[1]

Essentially, it refers to a residential structure with a very tight building envelope (Superinsulation). This minimizes the air changes per hour.[2] Emphasis is also placed on eliminating "thermal bridging" (conducting material which spans the building envelope) via which heat is easily lost.[2] Passive Houses are defined by their energy performance after construction, and the standard does not necessarily imply that any other form of environmentally friendly thought has gone into the construction (e.g. what is the environmental impact of producing the construction materials and how far they are transported).

Over 20,000 buildings certified to PassivHaus standards have been constructed across Northern Europe.[3]

These are the three basic requirement for passive houses:

  • It needs to have heating demands lower than 15 kWh per square meter annually (kWH/m2a).
  • The primary energy demands (for example warm water, heating, house appliances) need to consume lower than 120 kWH/m2a.
  • A passive house must pass a pressure test with a limited 50 Pascals and the pressure differentials must not be higher than 0.6 times a room's value per hour (n50 < 0.6 h-1)

Passive solar vs Passive House[edit]

The terms passive solar and passive house are often confused. The two terms refer to green building techniques and are closely related.

Passive solar design is about making best use of available natural light and heat. Heat from the sun is collected (if heating is desired, i.e. in a cool climate). A major part of passive solar design is careful orientation with respect to the sun. Passive solar is distinguished from active solar by the lack of operable devices.[2]

Passive House design is about managing heat loss and heat gain (not just from the sun but from all sources). The intended result is to have a structure that requires minimal energy to heat and cool.[2]

As such, some state that passive house design has greater applicability than solar design since orientation with respect to the sun is not absolutely necessary. Passive House design does not necessarily require a structure which is elongated along the east-west axis with extensive glazing on the equator facing side. Indeed, the ideal form of a passive house is a cube (lower surface area to volume ratio).[2] Passive solar houses are also said to be more complicated to design, and the internal temperature may fluctuate uncomfortably if they are designed poorly.[4] Greater savings can be obtained by building air tight with lots of insulation in walls and high R windows.[4]

However a more efficient approach would be to potentially utilise both passive solar and passive house design elements, which has been termed "Solar Passivhaus".[2]

Efficacy[edit]

Some sources state that structures built to PassivHaus standards require between 80-90% less heating costs than regular buildings.[3]

Cost[edit]

It is estimated that passive house buildings are 5-7% more expensive to build compared to regular buildings.[3]

See also[edit]

References[edit]

  1. Passive House (PassivHaus) website
  2. 2.0 2.1 2.2 2.3 2.4 2.5 Passive Solar Architecture Pocket Reference. D Thorpe. Earthscan from Routledge, 2018
  3. 3.0 3.1 3.2 Passive Solar Architecture: Heating, Cooling, Ventilation, Daylighting and More Using Natural Flows. D Bainbridge, K Haggard. Chelsea Green Publishing, 2011
  4. 4.0 4.1 Solar Versus Superinsulation: A 30-Year-Old Debate. Martin Holladay. Green Building Advisor, 2010