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PHIUS+ 2018: Getting to Zero

PHIUS+ 2018 is the first updated revision to the PHIUS+ 2015 standard,  and will fully replace PHIUS+ 2015 by April 2019 (see timeline). This update focuses on adding more nuance for different building types, and supporting an overall transition to renewable energy.

Space Conditioning

What’s the same

  • Pass/fail, “performance-based” passive building standard with prescriptive quality assurance requirements
  • Three pillars: limits on heating/cooling loads, limits on source energy use, required air-tightness & other prescriptive requirements
  • Climate-specificity, on a location-by-location basis

New in PHIUS+ 2018

  • Occupant density and building size (envelope to floor area ratio) influence heating/cooling load limits
  • Calculate Space Conditioning targets using the 'PHIUS+ 2018 Final Calculator' below.

Source Energy

What’s the same

  • Source energy used for overall energy budget
  • Source Zero available as add-on certification

New in PHIUS+ 2018

  • Source energy criteria tightened, on a path towards zero
  • No cap on total source energy, but rather on ‘Annual net source energy’, after offset by qualified renewable energy measures, on-site and off-site

The PHIUS+ 2018 source energy targets are:

  • Residential: 3840 kWh/person/yr
  • Non-Residential: 34.8 kBTU/ft2.yr


  • For buildings of five stories and above that are also of noncombustible construction:
    • q50 <= 0.080 CFM50/ft2 or q75<= 0.100 CFM75/ft2 of gross envelope area
  • For all other buildings:
    • q50 <= 0.060 CFM50/ft2 or q75<= 0.080 CFM75/ft2 of gross envelope area

PHIUS+ 2018 Final Calculator

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