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Analyzing the Impact of the Phius HRV/ERV protocol on North American Passive House Certification

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posted on 23.05.2021, 13:58 by Jimmy Tang
The stated heat recovery efficiency of HRV and ERV units in North American passive houses is dependent on the testing procedures and calculation methods established by several pertinent performance testing standards. This project highlights major differences between the applicable HRV/ERV standards for North American passive houses: the European Passive House Institute standard, the Canadian CSA-439-09 standard, and the American HVI-920 standard. It further examines the proposed PHIUS protocol which established ɳPHUIS, a modified HRV/ERV heat recovery efficiency rating to more accurately reflect the North American climate. Simulations were performed to quantify its effect on the modelled annual heat demand for 31 certified passive houses. The results yielded two key findings. First, the margin of error for the new rating, ɳPHUIS, relative to the existing rating, Ɛ, is a function of the regional climate given by the equation: y = 0.00001x + 0.0012. Locations with a colder climate have longer winters, thereby increasing the heating demand and intensifying the margin of error. Second, small to medium sized houses with floor areas (<250m2), which formed 90% of the sample study, have the largest impact on the margin of error up from 3.8% to 12% compared to large homes (>250 m2) from 2.8% to 4.2%. The results validate the necessity for PHIUS’ proposed ɳPHUIS for North American HRV/ERVs.





Master of Building Science


Building Science

Granting Institution

Ryerson University

LAC Thesis Type


Thesis Advisor

Russell Richman