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Net Zero Energy Homes

Net Zero Energy homes are the epitome of high-performance buildings.

The definition of a Net Zero Energy home is one that is designed, modelled and constructed to produce as much energy as it consumes on an annual basis.  These homes achieve this standard via the balance of reducing the amount of energy needed to operate and by generating energy on site through alternative energy sources.

By meeting this standard, homeowners are awarded with significantly reduced operating costs, a quiet and more comfortable living atmosphere, health benefits of high indoor air quality, and the satisfaction of making a significant contribution to the reduction of carbon emissions.

Watch a Net Zero Energy Housing video.

Built and designed by Effect Home Builders, the Belgravia Green project showcased various methods of achieving Net Zero Energy.  Three custom homes were constructed using a variety of techniques to display different ways of reducing energy consumption. The technology used is described below.

Technology in the Three Belgravia Green Homes:

Advanced Wall Systems

Foundation

Windows

Solar Electricity

Passive Solar

Insulation Products

Heating

Ventilation

Advanced Wall Systems

Two different methods of wall construction were chosen to achieve the high levels of insulation and air-tightness required.

One wall system is the 12” thick EnerGard Wall System.  This wall is constructed from engineered wood I-shaped wall studs, using expanded polystyrene as insulation, offering a NET R-value of 42.  The wall studs are coated in Pink Wood, a latex based covering that makes the structure fire and mould resistant.

The second wall system was a 16” thick wall created using a double-stud framing method.  This wall uses compressed cellulose insulation and achieves a NET R-value of 56.

Foundation

All three foundations were constructed using the Advantage ICF System. An additional layer of interior insulation was required to achieve the desired amount of insulation.  One method used was a 4” thick layer of expanded polystyrene.  A framed wall with batt insulation was the other method chosen. The result was a foundation with a NET R-40 insulation value.

Windows

Triple pane windows from All Weather Windows using three coats of low-e film, Argon insulating gas, and insulating spacers between panes were installed. The glazing was optimized to encourage solar energy to flow into the home while insulating to reduce heat loss to the outdoors.

Solar Electricity

Solar-electric systems using photovoltaic modules were used to generate energy. The arrays are grid-tied, meaning that the homes will provide energy to the electrical grid during the day, while drawing from the electrical grid during the evenings or when the home needs more energy than can be generated.

These systems were designed and developed by Howell Mayhew Engineering and installed by  Great Canadian Solar and DayStar Renewables.

Passive Solar

South-facing windows allow energy from the sun to be absorbed by the structural concrete floor. This thermal mass gathers the heat energy in the daytime, releasing it in the nighttime hours.

On this project, Hambro floor joists were used to carry the concrete floor.

Insulation Products

Expanded polystyrene (EPS) was used under the concrete floors in the basements. EPS is also part of the Plastifab Advantage Insulating Concrete Form, in the EnerGard advanced wall assembly, and as a method for adding additional insulation to the interior of basement walls. EPS is non-toxic, CFC-free, mould-free, and provides a stable insulating value that will not diminish with age.

Cellulose was compressed into the double stud wood framed walls and blown into the attics. Cellulose is made predominantly from post-consumer recycled paper.

Glass fibre batt insulation was used in the interior framed wall in the basement of the one of the homes. Glass fibre batts were chosen based on their high recycled content (73%) and performance characteristics.

Heating

Each home in Belgravia Green used a different heating system.

Geothermal heating

  • One home is heated with a geothermal, or Ground Source Heat Pump (GSHP) system. Geothermal heating requires a slightly higher initial investment, but runs at approximately 250% efficiency increasing long-term energy savings.

Electric baseboard heating

Air-source heat pump

  • The other is heated with an air source heat pump,  designed for cold weather climates. Efficiencies range from 100%-400% depending on outdoor temperature.

Ventilation

High efficient Heat Recovery Ventilators (HRV) were installed in each of the homes. These units provide fresh air by exchanging stale indoor air with fresh outdoor air. The incoming air is pre-heated by the exhausting air, recovering up to 88% of the heat. Electrical usage is low due to Electronically Commutated Motors.