3.1 Overview/Space Conditioning – Above Green

All of the requirements in Section 3.1.1 and 3.1.2 need to be met to achieve PHIUS+ Certification. The specific heating and cooling energy targets for the project will be determined by the envelope area, floor area, occupant density, and location of the project. Refer to the PHIUS+ 2018 Final Criteria Calculator to determine criteria for the project.

3.1.1 Main Performance Criteria for Certification

Annual Heating Demand2 ≤ A (kBTU/ft2 .yr)
Annual Cooling Demand2,3 ≤ B (kBTU/ft2 .yr)
Peak Heating Load2 ≤ C (BTU/ft2 .hr)
Peak Cooling Load2,3 ≤ D (BTU/ft2 .hr)
Airtightness4 ≤0.060 cfm/ft2 envelope @50Pa
Net Source Energy Demand5,6,7 ≤ 3840 kWh/yr/person

3.1.2 Summary of Other Requirements

Moisture design criteria for assemblies and details (see Section 3.4 and Appendix B)
Quality-related prescriptive design elements (see Section 3.5)
Field quality assurance inspections (see Section 3.6)
Contractor declaration (see Section 3.9)
Window Comfort Assessment (Section 3.11)

3.1.3 Optional Additional Certification Badges

Supply Air Heating and Cooling Sufficient 2

2 The space conditioning criteria are all per square foot of interior Conditioned Floor Area (iCFA). See Appendix H for details on the development of PHIUS+ 2018.

3 Annual Cooling Demand is total cooling, latent plus sensible. Peak Cooling Load target is sensible only.

Cooling criteria apply regardless of whether or not a cooling system is planned.

See Appendix C for method to evaluate when a cooling system is recommended. It is recommended in most climates especially for residential projects.

Certification staff may require that occupant-installed cooling, e.g. window A/C, is included in the energy model, even if it is not designed into the building as-delivered, so that the impact on source energy use is accounted for.

4 See detailed explanation in Section 3.2 below.

5 See Section 3.3 for further detail on alternate Net Source Energy targets for three “tiers”.

6 For residential buildings, occupancy is determined by the # of bedrooms + 1, per unit. 7 For non-residential buildings, the Net Source Energy limit is proportional to the floor area instead of occupancy. There is also a provision for “process load allowances” in some cases. See Section 3.3 for details.

3.1.4 Window Recommendations

It is generally recommended to follow the zone-by-zone guidelines on the PHIUS Certified Data for Window Performance Program page. As noted in Section 3.4 and 3.11 below, there is a “hard requirement” on window performance to avoid condensation risk, and to meet window comfort requirements.