As written by Tessa Smith, in the Green and Save article "Passive House vs. Passive Solar House," a Passivhaus is often misrepresented by the term used to describe passive solar houses that "rely on optimal orientation, large thermal masses for the collection of solar energy, and climates with dramatic diurnal swings.
There is a component of optimizing solar gains to a Passivhaus; it shares this in common with the solar movement, but its primary focus is conservation and minimizing of energy demands. The Passivhaus approach yields, in any climate, 75%-90% more efficient structures. Combine this with the other elements necessary to a Passivhaus, like ample fresh air delivery and high-performing windows, and you end up with a substantially more comfortable, affordable and healthy house."
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