New "jacket" for 1960s Bungalow

A new energy-efficient "jacket" cut this home’s energy use in half.

Building Type	Single-Family Bungalow (incl. 1.5 Story)	Location	Calgary, AB
Year Built	1968	Foundation Type	Concrete (Crawl Space)
Structure Type	Wood-Framed	Total Floor Area	189.2m²
Climate Zone	7a	Heating Degree Days	5000
Retrofit Status	Complete	Year Completed	2024
Retrofit Phasing	Yes	Geometry Changed	No
Annual Energy Savings	69.42%	Operational Carbon Savings	5.59 tCO2eq/yt

Project Team

SNAP Building ( Builder )
Sol Invictus Energy Services ( Energy Advisor )
Energuy Holdings LTD ( Energy Advisor )

Project Priorities

Reduce Energy Consumption
Achieve Net Zero or Net Zero Ready
Increase Thermal Comfort
Improve Indoor Air Quality
Reduce GHG Emissions
Repair and/or Renew Exterior

Upgrades

Attic insulation top up to R-60
Modified Larsen truss system added to exterior wall (Nominal R-35)
Triple pane Low-E coated windows
Upgraded Energy Star exterior doors
Insulated crawlspace wall and slab (Nominal R-9 and R-18, respectively)
Upgraded rim joist header insulation (Nominal R-32)
4″ of GPS Insulation added to upper portion of the foundation wall exterior. (Nominal R-18)
Improved air tightness, from 5.26 to 2.61 ACH @ 50 Pa
Heat pump domestic water heater (0.82 EF)
Energy Recovery Ventilator (ERV)

Project Description

Planning the Retrofit

This retrofit was driven by the homeowners goal to reduce greenhouse gas emissions and improve comfort in an older, drafty home. The house had cold spots in the winter, struggled to stay cool in the summer, and had outdated windows and insulation that did not perform well.

To address these issues, the project focused on improving the home’s building envelope. The plan followed an "envelope-first" approach to boost energy efficiency and comfort while lowering emissions.

Key Upgrades Included:

Exterior Walls: An 8" modified Larsen Truss system was added to the outside of the existing 2×4 framed walls, significantly improving insulation and reducing heat loss.
Air Barrier: A continuous air barrier was installed to seal leaks and improve airtightness throughout the home.
Attic Insulation: The attic insulation was topped up to reduce heat loss through the roof.
Foundation Walls: 4" of EPS (rigid foam) insulation was applied to the exterior foundation walls.
Crawlspace: Foam board insulation was added in the crawlspace below the addition to improve both insulation and airtightness.
Windows: Old, inefficient windows were replaced to eliminate drafts and improve year-round comfort.

Together, these improvements wrapped the home in a new, energy-efficient "jacket," cutting down on energy use, improving comfort in every season, and helping the homeowner meet their climate-conscious goals.

Getting to Net Zero

Once solar panels are installed on this home it will be net-zero in it’s electrical use.

Once the current natural gas furnace reaches end-of-life, an Air Source heat pump can be added as the primary heat source, achieving full Net-Zero performance directly or with some additional solar panels.

Before & After

General
	Before	After
Building Condition	Before General building upkeep maintained over the life of the building, dated construction.	After Modern high performance building techniques implemented. Building exterior modernized.
Comfort	Before Drafty building envelope with leaky windows.	After Quiet and comfortable building envelope, reduced temperature variance room by room and improved air quality.

Envelope
	Before	After
Ceiling/Attic Insulation	Before Ventilated attic with 2×4 truss on 24″ centers, nominal R-31 insulation.	After Insulation topped up to Nominal R-60
Ceiling/Attic Insulation	Before 29.6 R	After 46.6 R
Foundation Insulation	Before Main foundation consisted of a typical 2×4 frost wall with fiberglass batts, 8″ concrete foundation wall. Crawlspace slab and walls uninsulated.	After 4″ GPS board (R-20) added to exterior to 1 foot below grade. 2″ GPS (R-9.4) added to crawlspace walls and 4″ GPS (R-18.8) added to crawlspace slab.
Foundation Insulation	Before 11.7 R	After 18 R
Wall Insulation	Before Vinyl siding, 2×4 framing with R-8 fiberglass batts, gyp rock interior finish.	After Hardie board over 8” modified Larsen truss with 8″ inches of dense pack cellulose ( Nominal R-35).
Wall Insulation	Before 10.25 R	After 33.4 R
Windows and Doors	Before A mix of original 1960’s aluminum, updated 1990’s era vinyl and newer triple pane low-e window assemblies. (~R-2.1)	After Basement windows remain original, one double pane Low-E window, all other windows updated to triple pane Low-E (~R-4.5)
Air Changes per Hour	Before 5.26 ACH50	After 2.61 ACH50
Air Sealing	Before Typical leaky envelope for the period with 2 fireplace chimneys	After DuPont Tyvek Housewrap, sealed all windows and doors, other penetrations, ensured continuous air barrier from walls to soffit wherever possible.

Mechanical & Electrical
	Before	After
Heating	Before Condensing natural gas furnace (98% Steady State), Wood fireplace, Natural gas fireplace insert.	After Fireplaces removed and replaced with electric fireplaces for aesthetics. Furnace remaining until end of life.
Hot Water	Before 151 L Natural gas storage tank with pilot (0.55 EF)	After Integrated Heat Pump (189L, 0.82 EF)
Ventilation	Before Naturally aspirated, no whole home system.	After Energy Recovery Ventilator
Electrical Service	Before 100 Amps	After 200 Amps

Annual Energy Usage
	Before	After
Light and Appliance Energy Consumption	Before 12.1 GJ	After 11.34 GJ
Other electrical consumption	Before 14.52 GJ	After 14.04 GJ
Space Cooling	Before 0 GJ	After 0 GJ
Space Heating	Before 67.76 GJ	After 24.3 GJ
Ventilation Energy Use	Before 0 GJ	After 0.54 GJ
Water Heating	Before 26.62 GJ	After 3.78 GJ
Total Net Consumption (with Renewables)	Before 121 GJ	After 37 GJ
Total Annual Consumption	Before 121 GJ	After 54 GJ
Annual Cooling Demand Intensity	Before 0 kWh/m2/a	After 0 kWh/m2/a
Annual Electricity Consumption	Before 7500 kWh	After 8333 kWh
Annual Heating Demand Intensity	Before 99.48 kWh/m2/a	After 35.68 kWh/m2/a
Annual Natural Gas Consumption	Before 94 GJ	After 24 GJ
Energy Use Intensity	Before 177.65 kWh/m2/a	After 79.28 kWh/m2/a

Carbon Emissions
	Before	After
Annual Operational Carbon Emissions – Electricity	Before 3675 KgCO2e	After 1769.45 KgCO2e
Annual Operational Carbon Emissions – Natural Gas	Before 4944.45 KgCO2e	After 1262.41 KgCO2e

New "jacket" for 1960s Bungalow

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

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

After

Total Annual Consumption

Before