Net-Zero Split-Level

With a comprehensive deep retrofit including a renewal of the envelope, replacement of mechanical systems, and a solar PV installation, this Edmonton home is net-zero.

Building Type	Single-Family Split-Level	Location	Edmonton, AB
Year Built	1963	Foundation Type	Concrete (Full Basement)
Structure Type	Wood-Framed	Post-Retrofit Total Floor Area	211m²
Climate Zone	7a	Heating Degree Days	5120
Retrofit Status	Complete	Year Completed	2023
Retrofit Phasing	No	Geometry Changed	No
Annual Energy Savings	102.12%	Operational Carbon Savings	11.26 tCO2eq/y
Retrofit Type	Envelope and Mechanical	Performance Level	Net Zero

Project Team

Butterwick Construction ( Builder )
KBL Building Improvements ( Builder )

Project Priorities

Reduce Energy Consumption
Increase Thermal Comfort
Reduce GHG Emissions

Project Goals

With this deep retrofit, the family aimed to reduce their GHG emissions, reduce their energy consumption, and increase the comfort and functionality of their home along the way.

Upgrades

Envelope Improvements

Wall Insulation – Exterior – Larsen Truss
Attic / Roof Internal Insulation
Foundation Walls Exterior Insulation
Air Barrier

Windows and Door Improvements

Window Replacement – Triple Pane

Mechanical: Heating and Cooling Improvements

Air Source Heat Pump – Ducted

Mechanical: Ventilation Improvements

Energy Recovery Ventilator (ERV)

Mechanical: Hot Water Improvements

Heat Pump Water Heater (HPWH)

Renewables & Storage Improvements

Solar PV System

Electrical Improvements

Electrical Service Upgrade

Project Description

The Retrofit Story

The project team took a comprehensive approach, upgrading the building envelope from top to bottom, replacing mechanical systems with high-efficiency options, and adding solar PV to provide a renewable energy source.

The contractor dug out the exterior of the basement by hand and added insulation all the way to the footings. Two layers of basement insulation were installed: one layer of EPS foam against the wall and another layer of GPS on the outside. The EPS—geo-drain insulation board from Plasti-Fab—had slotted openings near the basement wall to direct water toward the weeping tile. This layer also added a valuable thermal top-up.

The exterior walls were built out using a Larsen truss-style double wall system supported by a box beam. This assembly created space for additional mineral wool batt insulation. Spray foam insulation was used in the box beam to provide both air sealing and thermal protection at the transition between foundation and wall.

To improve the roof, the team built a new structure over the existing cathedral roof. This created space for added insulation and allowed for an extended overhang to match the increased wall thickness. The assembly included TJI Truss Joists and perpendicular 2×6s, which formed both the overhang and an air gap between the insulation and sheathing.

New access paths were created to accommodate electrified mechanical systems, and the windows were upgraded to triple-pane. The building was then wrapped in a continuous air and vapour barrier.

At the same time, the owner carried out additional climate resilience and maintenance upgrades, including new exterior Hardie siding, standing seam metal roofing, and new soffits and eavestroughs.

Before & After

General
	Before	After
Building Condition	Before Original – Aesthetic Upgrades Only	After High-Performance / Passive House-Level

Envelope
	Before	After
Attic/Roof Assembly	Before Cathedral roof with fiber glass batts	After Additional roof structure with mineral wool batts added on top of existing structure and insulation
Attic/Roof Assembly Effective Thermal Resistance	Before R-11	After R-65
Wall Assembly	Before Fiberglass batt	After Mineral wool batt
Wall Assembly Effective Thermal Resistance	Before R-11	After R-37
Foundation Wall Assembly	Before No exterior insulation	After Exterior insulation added: R20 of EPS + R10 of GPS (main wall, box beam/above grade insulated with spray foam).
Foundation Wall Assembly Effective Thermal Resistance	Before R-8	After R-30
Windows and Doors	Before Mostly vinyl framing and double paned windows, one wood triple pane window, with R values ranging from R2 to R5	After All windows were replaced with triple pane PVC frames which were cladded with aluminium. Current R values range from 4 to 7.5.
Air Tightness	Before 2.94 ACH50	After 0.46 ACH50

Mechanical & Electrical
	Before	After
Cooling	Before No cooling	After Air Source Heat Pump: Daikin FTQ42TAVJUD + RZQ42TAVJU
Heating	Before Natural gas furnace, 71,000 BTU/h / 20.81 kW, at 80% AFUE	After Air Source Heat Pump (main source of heating): Daikin FTQ42TAVJUD + RZQ42TAVJU with 10 kW backup heat kit
Hot Water	Before Natural gas conventional	After Heat Pump Hot Water Heater: Rheem CPROPH80 T2 RH375-SO (80 Gal)
Ventilation	Before None	After Energy Recovery Ventilator: vänEE G3000E ECM
Renewables	Before None	After Solar Photo Voltaic: 15.47 kW (DC) / 13.056 kW (AC) Array
Electrical Service	Before 100 Amps	After 200 Amps

Annual Energy Usage
	Before	After
Total Annual Consumption	Before 169.67 GJ	After 42.04 GJ
Total Net Consumption	Before 169.67 GJ	After -3.59 GJ
Energy Use Intensity	Before 223.37 kWh/m2/a	After 55.35 kWh/m2/a
Annual Heating Demand Intensity	Before 154.13 kWh/m2/a	After 16.61 kWh/m2/a
Annual Cooling Demand Intensity	Before 0 kWh/m2/a	After 6.64 kWh/m2/a
Annual Electricity Consumption	Before 7,645.00 kWh	After 11,679.00 kWh
Annual Natural Gas Consumption	Before 142.15 GJ	After N/A
Light and Appliance Energy Consumption	Before 11.88 GJ	After 6.73 GJ
Space Cooling	Before 0 GJ	After 5.05 GJ
Space Heating	Before 117.07 GJ	After 12.61 GJ
Ventilation	Before 0 GJ	After 0.42 GJ
Water Heating	Before 27.15 GJ	After 3.36 GJ
Attic/Ceiling Heat Loss	Before 19.90 GJ	After 1.39 GJ
Main Walls Heat Loss	Before 19.90 GJ	After 2.14 GJ
Windows Heat Loss	Before 14.05 GJ	After 2.77 GJ
Exterior Doors Heat Loss	Before 1.17 GJ	After 0.38 GJ
Basement Foundation Heat Loss	Before 55.02 GJ	After 4.67 GJ
Air Leakage/Ventilation Heat Loss	Before 7.02 GJ	After 1.26 GJ

Carbon Emissions
	Before	After
Annual Operational Carbon Emissions – Electricity	Before 3,348.51 KgCO2e	After -437.12 KgCO2e
Annual Operational Carbon Emissions – Natural Gas	Before 7,477.18 KgCO2e	After N/A
Total Carbon Emissions	Before 10,825.69 KgCO2e	After -437.12 KgCO2e

Net-Zero Split-Level

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Project Team

Project Priorities

Project Goals

Upgrades

Envelope Improvements

Windows and Door Improvements

Mechanical: Heating and Cooling Improvements

Mechanical: Ventilation Improvements

Mechanical: Hot Water Improvements

Renewables & Storage Improvements

Electrical Improvements

Project Description

The Retrofit Story

Before & After

General

Building Condition

Before

After

Envelope

Attic/Roof Assembly

Before

After

Attic/Roof Assembly Effective Thermal Resistance

Before

After

Wall Assembly

Before

After

Wall Assembly Effective Thermal Resistance

Before

After

Foundation Wall Assembly

Before

After

Foundation Wall Assembly Effective Thermal Resistance

Before

After

Windows and Doors

Before

After

Air Tightness

Before

After

Mechanical & Electrical

Cooling

Before

After

Heating

Before

After

Hot Water

Before

After

Ventilation

Before

After

Renewables

Before

After

Electrical Service

Before

After

Annual Energy Usage

Total Annual Consumption

Before

After

Total Net Consumption

Before

After

Energy Use Intensity

Before

After

Annual Heating Demand Intensity

Before

After

Annual Cooling Demand Intensity

Before

After