Calgary Staged Retrofit

This project aimed to enhance the building envelope to a net-zero standard in preparation for future mechanical system upgrades. Now, achieving net-zero is a realistic objective, with additional improvements planned as existing systems reach the end of their service life.

Building Type	Single-Family 2+ Stories	Location	Calgary, AB
Year Built	1975	Foundation Type	Concrete (Full Basement)
Structure Type	Wood-Framed	Total Floor Area	312m²
Climate Zone	7a	Heating Degree Days	5000
Retrofit Status	Complete	Year Completed	2023
Retrofit Phasing	Yes	Geometry Changed	No
Annual Energy Savings	67.3%	Operational Carbon Savings	8.38 tCO2eq/yt

Project Team

SNAP Building ( Builder )
4 Elements Integrated Design ( Energy Advisor )

Project Priorities

Reduce Energy Consumption
Increase Thermal Comfort
Repair and/or Renew Exterior

Upgrades

Modified Larsen Truss added to exterior walls (Achieving R-39 Nominal)
Air/weather barrier installation and proactive air sealing on walls (2.05 ACH @50 Pa)
Upgraded windows to triple pane low-e, Argon (R 2.9-4.1)
Foam board insulation added to upper portion of exterior foundation wall.
Upgraded Hardie board exterior cladding
Heat Recovery Ventilator (83% Efficiency)
Solar PV system size increased over 3x
Radon mitigation

Project Description

Planning the Retrofit

The homeowner decided to stage this retrofit in order to extend the life of his existing mechanical and solar thermal systems. A long-time advocate for solar energy, he installed Calgary’s first grid-tied system back in 2001.

The retrofit strategy focuses on maximizing the efficiency of the building envelope to minimize the size and capacity required for future mechanical upgrades.

With the implementation of a net-zero rated wall assembly, insulation of the foundation walls, and upgraded windows, the only remaining envelope improvement will be the roof and attic.

Getting to Net Zero

Upgrades to the attic and roof assemblies and air sealing at the attic level will improve the air tightness and reduce the heating and cooling loads. The final envelope improvements and upgraded mechanical systems will get the building to net-zero.

Before & After

General
	Before	After
Building Condition	Before Original 1975 cedar and brick cladding, maintained over the years, but in need of an update.	After Updated modern cladding with enhanced curb appeal.
Comfort	Before Drafty building envelope with a few leaky windows. Road noise evident.	After Quiet and comfortable building envelope, reduced temperature variance room by room and improved air quality.

Envelope
	Before	After
Ceiling/Attic Insulation	Before Vaulted ceiling on the rear of the house was re-insulated and an improved vapour barrier installed around 2005. Spray foam insulation was added to front vaulted ceiling assemblies during roof replacement in 2015. Blown-in insulation in main attic	After No changes made to attic or ceiling area
Ceiling/Attic Insulation	Before 32.3 R	After 32.3 R
Foundation Insulation	Before Typical 2×4, 16 inch centers, mineral wool batts.	After 6″ of Type II EPS Foam board and/or GPS board added to upper portion of exterior foundation wall
Foundation Insulation	Before 11 R	After 15.16 R
Wall Insulation	Before Cedar wood lap cladding, 2×4 wood frame, 16 inch centers, R-12 to R-14 fiberglass/mineral wool batts, gyp rock interior finish.	After Original walls maintained, 8″ Modified Larsen Truss system installed outboard of existing wall structure and filled with dense packed cellulose insulation. (R-39.3 Nominal)
Wall Insulation	Before 11.2 R	After 37.6 R
Windows and Doors	Before A mix of recently updated triple pane Low-E, Argon filled windows and a few original windows.	After All windows except one original window upgraded to triple pane, Low-E, Argon filled. (R 2.9-4.1)
Air Changes per Hour	Before 4.3 ACH50	After 2.09 ACH50
Air Sealing	Before No proactive air sealing beyond spray foam being added to some window frames, typical weather stripping	After Updated weather/air barrier added to exterior wall over Modified Larsen truss, sealed building penetrations

Mechanical & Electrical
	Before	After
Heating	Before Condensing natural gas furnace (93.7 AFUE)	After No change
Hot Water	Before Natural gas instantaneous condensing hot water (tankless) (0.83 EF)	After No change
Ventilation	Before Naturally aspirated, no whole home system.	After Heat Recovery Ventilator (83% Efficient)
Renewables	Before 2,000 Watt grid-tied solar pv array, 2 collector solar thermal array	After 8.6 Solar PV array with a two collector solar thermal collector system that yields ~1 GJ/month
Electrical Service	Before 100 Amps	After 100 Amps

Annual Energy Usage
	Before	After
Light and Appliance Energy Consumption	Before 12.18 GJ	After 12 GJ
Other electrical consumption	Before 13.92 GJ	After 14 GJ
Space Cooling	Before 0 GJ	After 0 GJ
Space Heating	Before 132.24 GJ	After 59 GJ
Ventilation Energy Use	Before 0 GJ	After 0 GJ
Water Heating	Before 15.66 GJ	After 15 GJ
Total Net Consumption (with Renewables)	Before 159 GJ	After 52 GJ
Total Annual Consumption	Before 174 GJ	After 100 GJ
Annual Cooling Demand Intensity	Before 0 kWh/m2/a	After 0 kWh/m2/a
Annual Electricity Consumption	Before 7222 kWh	After 7222 kWh
Annual Heating Demand Intensity	Before 117.74 kWh/m2/a	After 52.53 kWh/m2/a
Annual Natural Gas Consumption	Before 148 GJ	After 74 GJ
Energy Use Intensity	Before 154.91 kWh/m2/a	After 89.03 kWh/m2/a

Carbon Emissions
	Before	After
Annual Operational Carbon Emissions – Electricity	Before 1497.22 KgCO2e	After -2994.45 KgCO2e
Annual Operational Carbon Emissions – Natural Gas	Before 7784.88 KgCO2e	After 3892.44 KgCO2e

Calgary Staged Retrofit

Project Team

Project Priorities

Upgrades

Project Description

Planning the Retrofit

Getting to Net Zero

Before & After

General

Building Condition

Before

After

Comfort

Before

After

Envelope

Ceiling/Attic Insulation

Before

After

Ceiling/Attic Insulation

Before

After

Foundation Insulation

Before

After

Foundation Insulation

Before

After

Wall Insulation

Before

After

Wall Insulation

Before

After

Windows and Doors

Before

After

Air Changes per Hour

Before

After

Air Sealing

Before

After

Mechanical & Electrical

Heating

Before

After

Hot Water

Before

After

Ventilation

Before

After

Renewables

Before

After

Electrical Service

Before

After

Annual Energy Usage

Light and Appliance Energy Consumption

Before

After

Other electrical consumption

Before

After

Space Cooling

Before

After

Space Heating

Before

After

Ventilation Energy Use

Before

After

Water Heating

Before

After

Total Net Consumption (with Renewables)

Before