A hard working, net zero energy home in an older neighbourhood producing energy for its owners, now and long into the future.
We challenged ourselves to build a net zero energy home in a mature neighbourhood at a time when this concept was virtually unheard of. This project included three homes on three adjoining lots. Two of the homes were built as envisioned by the owners of those lots, but Belgravia Green was our show home, which gave us the freedom to try out new and innovative ideas.
We wanted to achieve the net zero energy target while taking advantage of beautiful south facing views, and do all this with an attractive design. Because our goals were pretty ambitious and at the same time cutting edge, there were obstacles to overcome. For example, we needed to work within municipal building setback and design requirements which did not necessarily address the types of design that would permit us to achieve our environmentally friendly objectives. Also, having chosen a mature neighbourhood, we had to work around solar shading from the mature boulevard trees in front of the home.
The ability to build the home to our specifications and requirements, also permitted us to showcase some of this new technology to interested parties, including the City, neighbours, utility suppliers and prospective clients.
Our goal was to build an innovative home that was aesthetically striking but didn’t feel like net zero energy performance was the primary objective. It was all about optimizing what nature has to offer without compromising beauty and functionality. To come up with the creative solutions, we held collaborative meetings with architects, designers, engineers, subject matter experts, municipal representatives and prospective homeowners to explore and share a broad diversity of design ideas.
South facing windows were strategically placed in front of a concrete floor to optimize passive solar gain which reduced the home’s heating needs by 32%. Photovoltaic solar panels were installed on the house and garage to produce electricity. Energy efficient heating system, appliances, on demand hot water heating and water-conserving plumbing fixtures were chosen to consume as little energy as possible, enhancing a modern and comfortable space for future homeowners.
Net zero energy homes consume just as much power as they produce, and diligent planning has ensured the Belgravia Green Home achieves this – and then some!
The 12.5kw solar-electric system installed on the house and garage produce 100% of the energy needed to heat and power the home. This is significant as the climate can be cold in Edmonton, the northernmost metropolitan area in North America with a population of over one million.
Energy Conserving Building Envelope
The Belgravia Green Home uses 12” thick engineered walls insulated with expanded polystyrene (R48), Insulated Concrete Form foundation with additional insulation (R41), 4″ under-slab insulation (R16), blown in cellulose in the attic space (R100), and strategically placed triple-pane windows (which are argon gas-filled with three coats of high solar heat gain coefficient low-e film). The envelope was carefully sealed for airtightness, measured at 0.59 air exchanges per hour. The house was certified as a very early entry into the Canadian Home Builders’ Association’s Net Zero Energy Labelling Program.
Passive solar heating
The placement of the house on the lot maximizes passive solar space heating. Large south-facing windows combined with a 4” thick thermal mass of polished concrete on both main and basement floors store the sun’s heat and provide free passive solar space heating delivering up to 32% of the home’s annual heating consumption.
As well as assisting with heating, the home’s polished concrete floors are among the easiest floors to clean and maintain, plus they’re extremely durable. They contribute to cleaner air by not containing undesirable chemicals, such as glues and formaldehyde, often found in other floor coverings.
Heat Recovery Ventilation (HRV)
The Belgravia Green Home’s heat recovery ventilator is 88% efficient. This is achieved by preheating incoming fresh air with heat energy from warm exhausting air. This greatly reduces the amount of heat required to bring the fresh air up to room temperature and is an efficient way of providing ventilation in a healthy home.
We created an entertainment space above the home for the homeowners to enjoy the south-facing view of the neighbourhood park. The roof deck also provides easy access for clearing snow off the solar array in the winter months should the homeowners wish to further improve solar energy production.