1959 Bungalow Net-Zero Ready Retrofit

Thanks to a net-zero-ready retrofit all about boosting comfort and cutting energy use, this bungalow sips energy instead of guzzling it.

Building Type	Single-Family Bungalow (incl. 1.5 Story)	Location	Calgary, AB
Year Built	1959	Foundation Type	Concrete (Full Basement)
Structure Type	Wood-Framed	Total Floor Area	178.1m²
Climate Zone	7a	Heating Degree Days	5000
Retrofit Status	Complete	Year Completed	2022
Retrofit Phasing	No	Geometry Changed	No
Annual Energy Savings	58.77%	Operational Carbon Savings	1.77 tCO2eq/yt

Project Team

Solar Homes Inc ( Builder )
Verda Tech Energy Management ( Energy Advisor )
4 Elements Integrated Design 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
Improve Home Value

Upgrades

Updated windows (double pane, Low E)
4″ Roxul (R-16) added to above grade walls
Hardie board siding
Spray foam insulation in attic + blown cellulose top up to R-56
2.5 tonne Daikin heat pump
AO Smith heat pump water heater
Gas service disconnected
Additional R-20 added to exterior basement walls
Heat Recovery Ventilator (HRV)

Project Description

This deep retrofit began with a family’s desire for a cozier, more efficient home. The homeowner also mentioned that there was frost forming inside on the closet walls. Working with Solar Homes and their energy advisor, who assessed their home’s weak points, they developed a plan that prioritized the most effective upgrades. The builder recommended starting with better insulation and window replacement to improve heat retention, followed by installing a Daikin heat pump and AO Smith heat pump water heater to boost efficiency. This strategic plan allowed them to confidently disconnect from natural gas, resulting in lower energy bills, improved comfort, and a greener, healthier home they now take pride in.

The envelope improvements did much of the heavy lifting, and the home is now ready for a solar PV system to bring them to net-zero.

Before & After

General
	Before	After
Building Condition	Before Dated exterior, half rock dash stucco, half wood lapped exterior finishing. The building appeared to be in good shape for the age.	After Sleek and simple aesthetic, more characteristic of a modern build. Uniform Hardie board exterior finish with updated windows.
Comfort	Before Large windows and bulky corner framing likely resulted in some convective currents. Possible feeling of drafts as a result. Noise levels characteristic of a 2×4 framed home.	After Improved air quality and air tightness, vastly improved conductive losses, comfortable temperature management, reduced worry of CO with removal of the gas service.

Envelope
	Before	After
Ceiling/Attic Insulation	Before Asphalt roofing material, 3/8″ plywood decking, 2×4 trusses 24″ on center, R-24 blown-in insulation, 3/8″ plywood decking, 1/2″ drywall interior finish.	After Original insulation removed and attic floor sealed with closed cell spray foam and blown insulation added on top to bring assembly to R56
Ceiling/Attic Insulation	Before 25 R	After 53 R
Foundation Insulation	Before 8″ concrete wall, 3/4″ airgap, 2×4 framing 16″ on center, R-12 fiberglass batt insulation, 1/2″ drywall interior finish.	After Foundation wrapped on exterior with R20 of XPS foam insulation to 18″ below grade.
Foundation Insulation	Before 10 R	After 21 R
Wall Insulation	Before 50/50 rock dash stucco and wood lapped exterior siding, 3/8″ OSB sheathing, 2×4 framing 16″ on center, R-8 paperback fiberglass batts, 1/2″ drywall interior finish	After Hardie board siding, 1×3 strapping at 24″ on center, 4″ Roxul rock wool batts, 20 mil house wrap over top of existing assembly.
Wall Insulation	Before 10 R	After 27 R
Windows and Doors	Before A mix of updated windows and doors from the late 90’s early 2000’s and original windows. (~R-2.6)	After Existing windows and new double pane vinyl windows and new doors (~R-2.8).
Air Changes per Hour	Before 2.73 ACH50	After 1.05 ACH50
Air Sealing	Before No proactive air sealing beyond spray foam being added to some window frames.	After House wrap, spray foam added to attic decking, spray foam added to window frames, addition of Roxul on exterior also improved air tightness.

Mechanical & Electrical
	Before	After
Heating	Before Condensing natural gas furnace (92.5% AFUE)	After Daikin 2.5 ton heat pump (3.46 COP), electric resistive heat backup (100% Steady State)
Cooling	Before None	After Daikin 2.5 ton heat pump (2.22 COP)
Hot Water	Before Natural Gas Storage Tank With Pilot Light (151L, 0.62 EF)	After AO Smith Air source heat pump hot water tank (0.90 EF)
Ventilation	Before Naturally aspirated, no whole home system.	After Heat Recovery Ventilator (HRV) (70% Efficient)

Annual Energy Usage
	Before	After
Light and Appliance Energy Consumption	Before 11.4 GJ	After 11.75 GJ
Other electrical consumption	Before 13.68 GJ	After 14.1 GJ
Space Cooling	Before 0 GJ	After 2.82 GJ
Space Heating	Before 64.98 GJ	After 14.1 GJ
Ventilation Energy Use	Before 0 GJ	After 0.47 GJ
Water Heating	Before 23.94 GJ	After 3.76 GJ
Total Net Consumption (with Renewables)	Before 114 GJ	After 47 GJ
Total Annual Consumption	Before 114 GJ	After 47 GJ
Annual Cooling Demand Intensity	Before 0 kWh/m2/a	After 4.4 kWh/m2/a
Annual Electricity Consumption	Before 7222 kWh	After 13056 kWh
Annual Heating Demand Intensity	Before 101.35 kWh/m2/a	After 21.99 kWh/m2/a
Annual Natural Gas Consumption	Before 88 GJ	After 0 GJ
Energy Use Intensity	Before 177.8 kWh/m2/a	After 73.3 kWh/m2/a

Carbon Emissions
	Before	After
Annual Operational Carbon Emissions – Electricity	Before 3538.89 KgCO2e	After 6397.23 KgCO2e
Annual Operational Carbon Emissions – Natural Gas	Before 4628.85 KgCO2e	After 0 KgCO2e

1959 Bungalow Net-Zero Ready Retrofit

Project Team

Project Priorities

Upgrades

Project Description

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

Cooling

Before

After

Hot Water

Before

After

Ventilation

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

After

Annual Cooling Demand Intensity