08/02/12 - As if Living Building Challenge was not enough of a challenge, Randy was intrigued with the Passive House energy modeling program. Could the Urban Frontier House meet the Passive House criteria as well? On August 2, 2012 we signed an agreement with a Passive House energy consultant to assist us with modeling of our new house. The “gist” of the program is to make the house extremely well insulated without too many thermal breaks in order to significantly reduce the energy demand for either heating in the winter or cooling in the summer. That seemed like a good idea – easier said than done. The consultant ran our house measurements, number of windows, number of doors, etc. through the Passive House calculation software. Our house design exceeded the annual energy per square foot threshold. Bummer! Back to the drawing board. I can’t even remember how many times we tweaked the plan and held our breath waiting for the results. Each time was a “Close, but No.” An apparent flaw in the system is that the Passive House modeling software could not “understand” and address certain aspects of our house design such as the airflow through the garden room. Perhaps in time that will change. The good news is that by going through the process, we became more cognizant of such things as real insulation needs including insulation under the basement slab and window sizes on the north side of the house versus window sizes on the south side of the house. Therefore, we feel that all was not lost and the house design is better because of it.