The River Forest house has been submitted to PHIUS for the PHIUS+ certification process, and I am occasionally asked what the incentive is--what are we getting for the $2700-ish in fees? The answer is twofold: 1.) expert review of the design; and 2.) third-party verification of the construction.
I recently received comments from the first review, and look on it as a kind of finishing school for PHPP, since it's being done by one of the most seasoned PHPP users in the country. I had missed some major opportunities for summer and night ventilation as well as interior shading, all of which drastically reduced my cooling loads, and therefore my Primary Energy. There is also an interesting issue with houses above PHPP's expected floor-area-per-person range: internal heat gains, which are significant in such super-insulated, airtight houses, get lower the more floor area per person. So we had to take a close look at appliance loads and expected plug loads. As covered in the "Klingenblog," US houses are proving to be higher in electrical use than PHPP predicts, affecting internal heat gains as well, so that is an important item to accurately predict: how many TVs? Will there be a server running continuously? Her coverage of Blake Bilyeu's house in Oregon was an eye-opener regarding electrical use. And finally, there is always the benefit of peer review--I had missed two windows and some shading factors, and having someone looking over your shoulder makes you catch those.
The project is back to PHIUS, and we hope to get our pre-certification notice soon. Construction is starting next week, and the ICF forms have been delivered. Once construction is underway, the next phase of the PHIUS+ program begins, in which Andy Scott of Energistics will show up on site for QA/QC, including inspecting the insulation installation and performing blower door test. In short, PHIUS+ is providing us with certainty that the house we have designed is accurately modeled, and that construction quality is assured.
Update: we're the happy recipients of pre-certification: