New Passive House standards offers prescriptive path that reduces costs
By Peter Fabris, Contirbuting Editor
The latest Passive House Institute U.S. (PHIUS) standard, expected to be released early next year, contains a prescriptive path option that could reduce the cost of certification.
Passive House 2021+ is expected to include the ability to achieve certification without a requirement for a Passive House consultant and the attendant modeling that goes with it. The Prescriptive Design Review checklist is four pages plus footnotes. It is similar to ENERGY STAR rater checklists.
The new Prescriptive Path provides an online calculator that requires a few entries to determine minimum R-values and maximum window U factor. These provisions include a window U factor maximum of .25, R-31 for cantilevered floors, R-61 for roof or ceiling insulation, and R-20 for slabs and floors over unconditioned space. Alternatively, one can provide a calculation that meets the same overall UA as the prescriptive requirements. This allows for tradeoffs.