Award-Winning Larsen Truss Deep Energy Retrofit

This deep energy retrofit re-imagined a 1997 Bow Valley home with a bold push toward reducing carbon emissions to net-zero, improving comfort, and enhancing indoor air quality.

Building Type Single-Family 2+ Stories Location Canmore, AB
Year Built 1997 Foundation Type Slab-on-Grade
Structure Type Wood-Framed Post-Retrofit Total Floor Area 202m2
Climate Zone 7a Heating Degree Days 5000
Retrofit Status Complete Year Completed 2023
Retrofit Phasing No Geometry Changed Yes
Annual Energy Savings 94.58% Operational Carbon Savings 7.54 tCO2eq/y
Retrofit Type Envelope and Mechanical Performance Level Net Zero

Project Team

Project Priorities

  • Achieve Net Zero or Net Zero Ready
  • Reduce GHG Emissions
  • Increase Thermal Comfort

Upgrades

Envelope Improvements

  • Wall Insulation – Exterior – Larsen Truss
  • Attic / Roof Internal Insulation

Windows and Door Improvements

  • Window Replacement – Triple Pane
  • Door Replacement – High Performance

Mechanical: Heating and Cooling Improvements

  • Ground Source Heat Pump (Geothermal)
  • Gas / Fossil Fuel Disconnection

Mechanical: Ventilation Improvements

  • Heat Recovery Ventilator (HRV)

Mechanical: Hot Water Improvements

  • Electric Hot Water Tank

Electrical Improvements

  • Full Electrification

Structure and Space Improvements

  • Interior Renovation

Project Description

The Retrofit Story

This project won the Residential Award at the 2023 Prairie Wood Design Awards. It features a deep energy retrofit of a 1997 two-storey home which had existing solar PV and solar hot water systems. The retrofit was designed with Passive House principles in mind. Openings facing the South were enlarged and windows were upgraded. Additional insulation was provided with a 9 ½” Larsen truss system filled with Rockwool insulation. The gas line and solar hot water system were abandoned, and a deep well open-loop geothermal system and heat pump were installed, along with a heat recovery ventilator (HRV) for fresh indoor air supply. More solar PV panels were added after the second EnerGuide Evaluation to make the building net zero. The interior was also refreshed and an entry room was added. The slab-on-grade foundation had originally been constructed with the slab poured inside a stem wall, so the team dug down 18" around the exterior of the foundation and added 4" of XPS insulation.

Lessons Learned

Stucco was removed where Larsen truss attachments were located, with all the window trims, belly bends, and penetrations having no stucco below.

In hindsight, removing all the stucco would have been easier. This would have left a clean surface for mounting TJI’s directly to the framing instead of using spacers.

Before & After

General

Envelope

Mechanical & Electrical

Annual Energy Usage

Carbon Emissions

Technical Documents

Drawings or Details

Photos

Pre Retrofit

During Construction

Post Retrofit