See Phius in Action in Minnesota

Achieving Phius Certification in Minnesota's Cold Climate

Minnesota’s climate zones range between 6A and 7 zones. Some of the coldest in the US, Phius passive building principles optimize energy efficiency and thermal comfort in Minnesota's cold climate through a combination of design attributes:

Design Guidelines

1. Simple and Compact Massing
   The building form is kept compact, minimizing exposed surface area to reduce heat loss and improve energy efficiency. Spaces are organized for thermal efficiency and ease of heating, concentrating living areas within a tightly planned layout.
2. Glazing and Shading Optimization
   Window placement, size, and shading elements are strategically designed to maximize solar heat gain in winter while mitigating overheating during summer. The design prioritizes natural daylighting and framed views of the outdoors and minimizing north-facing windows and optimizing south-facing windows.
3. Triple-Pane Windows
   High-performance windows with triple glazing and insulated frames minimize thermal bridging and ensure a tight thermal envelope.
4. Airtight Construction
   The building envelope achieves stringent airtightness standards to prevent infiltration of cold air and leakage of conditioned air, maintaining indoor comfort and reducing energy demand and mechanical equipment sizing.
5. High Insulation Levels
   1. Walls: R-40+
   2. Roof: R-70+
   3. Underslab: R-25+
      These robust insulation levels significantly reduce heat loss and improve year-round energy performance.
6. Heat and Energy Recovery Ventilation (HRV/ ERV)
   A heat recovery system ensures efficient ventilation, maintaining fresh indoor air quality while minimizing heat loss in exhaust air.
7. Cold Climate Heat Pump
   A specialized heat pump system efficiently provides heating and cooling even in extreme cold temperatures with defrost settings aligning with the Passive House standard's emphasis on low energy consumption.

This combination of design and performance strategies enables Phius passive buildings to deliver superior energy efficiency, resilience, and comfort tailored to Minnesota’s challenging climate.

Annual Site Energy Use Comparisons — Small Multifamily