“Passive House” is a building standard that applies to all types of constructions. It is a set of guidelines that assures quality in construction. The main principles of Passive House, regardless of which local standard you consider, are continuous insulation, air tightness, mitigation of thermal bridges, indoor air quality with heat recovery, and high performance windows and doors.

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For further basic clarification check out this Houzz article Mariana wrote in 2013, explaining the various nuances of the word “passive”:

The term “passive” is getting thrown around almost as frequently as the word “green” these days. But what does it actually mean? And how does the all-encompassing adjective differ from the measurable standards of the capitalized Passive House?