The Passive House Design Criteria
Is a German-built standard that has proved to achieve remarkable results, it is the most energy efficient criteria worldwide as it saves energy up to 70-90% comparing to the conventional buildings. It is the leading global standard in energy-efficient construction to improve the building energy performance by defining a set of design and construction principles used to achieve this standard. while achieving sufficient indoor air quality conditions and providing high levels of thermal comfort as well.
The Five principles are key to the Passive House concept
- Thermal insulation: All opaque building components of the exterior envelope of the house must be very well-insulated with specific heat transfer coefficient (U-value) for every climate.
- Passive House windows: The window frames must be well insulated and fitted with low-e glazing filled with argon or krypton to prevent heat transfer. with specific heat transfer coefficient (U-value) & g-value for each climate.
- Ventilation energy recovery: Efficient energy recovery ventilation is key, allowing for a good indoor air quality and saving energy. In Passive Houses, at least 75% of the energy from the exhaust air is transferred to the fresh air again by means of a heat exchanger.
- Airtightness of the building: Uncontrolled leakage through gaps must be smaller than 0.6 of the total house volume per hour during a pressure test at 50 Pascal (both pressurized and depressurized).
- Thermal bridges free design: 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 minimized as far as possible.
The official definition of the Passive House, according to the official PHI website, is “Passive House is a building standard that is truly energy efficient, comfortable and affordable at the same time.”. Moreover, it is concerned with the indoor air quality by providing nonstop fresh air which thermal comfort (ISO 7730) could be reached out solely by post-heating or post-cooling of the fresh air.
The concept of Passive House is recovering energy through intelligent design, reaching the desired goal of using environmental architecture at the lowest possible cost even without renewable resources. That does not mean that PH avoids or does not favour the use of renewable energy, but the PH criteria were able to reach this achievement of ultra-low energy buildings even without using renewable resources.
There are specific principles to reach the PHC set by the German institution while at the same time achieving the comfort and optimum indoor air quality inside these buildings. These principles are essential to achieve the PHI requirements, then give the building access to be Certified Passive House building, whether a new building or retrofitted one. The PH components vary depending on the nature of the structure, location, orientation, and climate.