The Philadelphia passive project

The inspiring 100K house project in Philadelphia, which aims to build affordable, environmentally friendly housing, has announced a new initiative to build two houses to the Passive House standard (which can reduce energy for heating and cooling by over 90%):

We will definitely return to LEED after this project, but we see the Passive House standard as a great way to improve some very specific aspects of our houses, mainly the envelope and the mechanical systems. In these two areas, Passive House far exceeds even the highest standards of LEED.

The goal, as always, is to pursue this new standard in an affordable manner ... Our goal is to adhere to the same requirement as the 100k House project and build this home for less than $100 per square foot in hard construction costs. With any luck this will allow us to provide one of the most affordable Passive Homes ever built in the US.