One of the presentations I attended at the Passive House conference in Portland, Maine, on September 22, 2014 was a session called “Passive House certifiers’ roundtable.” The first speaker on the panel, Tomas O’Leary, explained that he usually charges about $2,200 to certify a residential Passivhaus project. He warned the audience that certification is “quite an effort; don’t underestimate it.”
Tomas advised that anyone interested in certifying their Passivhaus should remember the following important steps:
- Prepare, collate, and submit the construction and mechanical details.
- Photograph all critical details.
- Make sure you get an HRV commissioning report.
- Remember that your blower-door test has to be performed twice: under both pressurization and depressurization conditions.
- Make sure that you enter the right climate data into PHPP; data from a nearby weather station might not be good enough.
- Enter the correct U-factors for all of the window components — Uframe, Uedge, Uglass — because each component has to be modeled.
- The R-value per inch of all relevant materials has to be documented. Listing the R-values is insufficient; each R-value requires a document that justifies the listed value.
- Document a 360 degree panorama of the shading situation at the building site.
Is each one of these details really essential for determining whether a house can be certified as a Passivhaus? Absolutely.
If you are in any doubt about this issue, remember that one of the cited causes of the famous divorce between the Passivhaus Institut in Germany and Passive House Institute U.S. was a dispute over the details of the certification documents for a house in Canada. The dispute centered on two points: whether the efficiency calculations for a Canadian HRV met the strict efficiency calculation requirements specified by the German institute; and whether an evergreen tree was tall enough to invalidate the shading calculations entered into PHPP.