Skip to main content

- What is Passive Building?
  Your passive building questions, answered
  
  Passive Building
  
  Passive Building Principles
  
  Passive Building FAQs
  
  A Better Way to Zero
  
  Passive Building Foundations Training
- Sectors
  Passive isn't just for houses
  
  Single-Family
  
  Multifamily
  
  Office Buildings
  
  Schools
  
  Other Non-Residential
- Projects
  Phius Certified Projects are the most energy efficient and comfortable buildings in the world
  Find a Project
  
  Project Certification
  
  Submit a Project
  
  Certification Review Queue
- Products
  Phius Certified Products are guaranteed to perform to passive standards
  View Products
  
  Product Certification Overview
  
  Window Certification
  
  Panel Certification
- Professionals
  Phius Certified Professionals are on the cutting edge of high-performance building
  Find a Professional
  
  Phius Certified Consultant (CPHC®)
  
  Phius Certified Builder (CPHB)
  
  Phius Certified Rater
  
  Phius Certified Verifier
  
  Phius Certified Trades Professional
  
  Phius Associate
  
  Maintain Credentials
Our Approach
- New Construction
  Phius CORE and Phius ZERO provide the path for constructing a Phius building from the ground up.
- Retrofit
  Upgrade existing buildings to Phius standards using Phius CORE REVIVE and Phius ZERO REVIVE.
- Commercial
  Phius standards aren't just for residential buildings. Phius CORE COMM and Phius ZERO COMM can be applied to any non-residential building.
Categories
February 17 – 27

Phius Certified Builder Training and Certification Exam | February 2026
Become a Phius Certified Builder!
Upcoming Sessions
- Phius Certified Builder Training and Certification Exam | February 2026
  February 17 – 27
- Phius Certified Consultant Training & Certification Exam | February 2026
  February 17 – 27
- Member Office Hours - Project Questions
  February 24
- Webinar: Marketing Passive Building Part 2
  February 25
- Policy Work
  Promoting policies designed to grow passive building
  Policy Database
  
  Financial Incentives
  
  Codes
  
  Qualified Allocation Plans
  
  Cost Data
- Tools and Support
  Providing the tools you need to create healthier buildings
  Resource Library
  
  Certification Support
  
  Calculators and Protocols
  
  Feasibility Study
  
  METr Design Tool
  
  WUFI Passive Design Tool
  
  Climate Data
  
  Quality Assurance
  
  Tech Corner

Project 1995

121 Prospect

Somerville, Massachusetts

Building Function

Multifamily
Project Type

New Construction
ASHRAE Climate Zone

5A - Cool - Humid
Status

Design Certified
INT. Conditioned Floor Area

25967 ft²

Core Project Team

Phius CPHB

Vincent Carbonneau
Phius Certified Verifier

Michael Browne
Phius CPHC (Lead)

Vitor L. Goncalves
Project Submitter

Rebecca O'Hearn
Primary Reviewer

Neil Rosen

Project Information

- Building Function
  
  Multifamily
- Project Type
  
  New Construction
- Number of Units
  
  32
- Number of Stories
  
  4
- Program Version
  
  Phius CORE 2021
- All Electric
  
  Yes
- INT. Conditioned Floor Area
  
  25967 ft²
- Status
  
  Design Certified
- Design Certification
  
  January 6, 2025
- ASHRAE Climate Zone
  
  5A - Cool - Humid
- Region
  
  Northeast

Performance

- Annual Heating Demand
  
  3.04 kBTU/ft².yr
- Annual Cooling Demand
  
  3.8 kBTU/ft².yr
- Peak Heating Load
  
  3.59 kBTU/ft².yr
- Peak Cooling Load
  
  3.04 kBTU/ft².yr
- Site Energy Use Index (EUI)
  
  21.57 kBTU/ft².yr
- Compliance Software
  
  WUFI Passive
- Source Energy (Residential)
  
  3518 kWh/person.yr
- Air Tightness (per enclosure area)
  
  0.06 CFM50/ft²

Enclosure

Systems & Equipment