Using the Sun and the Earth to Stay Warm
By Wendy Priesnitz

This Quebec house is designed to produce as much energy from solar and geothermal as it consumes.

ÉcoTerra™, a 1,500 square-foot home in Eastman Quebec, not only produces as much energy as it consumes in a year (a net-zero energy home), but also features a healthy indoor environment, low environmental impact, significant resource conservation and affordability. Factory pre-engineered modular sections were used to optimize construction quality and reduce construction as well as environmental impact at the site.

The R-2000 house, by builder-developer Les industries Ste-Anne de la Rochelle, Inc. (Alouette Homes), was chosen as one of the winners in Canada Mortgage and Housing Corporations’ Equilibrium project. Formerly known as the Net-Zero Energy Healthy Housing program, the initiative brings the private and public sectors together to develop homes, and eventually communities, that address occupant health and comfort, energy efficiency, renewable energy production, resource conservation, reduced environmental impact and affordability. Houses built with the assistance of the program are monitored to assess their performance, and are open to the public for tours.

The total annual energy requirement for the home is predicted to be equal to the on-site annual production from renewable energy sources: active and passive solar space and water heat, a geothermal heat pump and photovoltaic electrical panels. That energy requirement is predicted to be only 17 percent of that for the average Canadian home.   

ÉcoTerra™ includes a living room, dining room, kitchen and two-piece bath with laundry on the main floor, and two bedrooms, an office and four-piece bath on the second floor. The second floor is constructed with movable interior walls in order to accommodate the occupants’ changing needs.

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The well-insulated building envelope significantly reduces space heating requirements and the house is oriented to maximize solar gain. Special attention has been given to daylighting, with large south-facing windows and open spaces that increase light penetration to the main floor. Roof overhangs are used to prevent overheating from solar gain. Energy-efficient, triple- glazed, low-e, argon-filled windows contribute to the reduction in heat loss. Thermal mass materials, which store heat and moderate interior heat fluctuations, include the concrete floor and half wall in the family room, and concrete slab and walls in the basement. Drain water that would otherwise escape from the house is captured with a heat recovery exchanger.

ÉcoTerra™ utilizes a building integrated photovoltaic system combined with a heat recovery system. A three kW Uni-Solar PV array, composed of 21 PV film sheets laminated to a standing-seam metal roof, is connected to a DC/AC inverter. The inverter connects through the electricity meter to the grid. Solar heat generated at the roof-top system is captured and then distributed in the home, assisting with space heating, domestic water heating and clothes drying. Removing this excess heat from the vicinity of the array also improves its efficiency. To further reduce energy costs, a three-ton, two-stage geothermal heat pump provides space and water heating.

On the 2.7-acre forested lot, a system of streams and storm water management ponds provide erosion control. A rain barrel system captures roof run-off for garden watering.

The airtight construction, combined with a heat recovery ventilator, is also a key health feature of the home. In addition, the pre-engineered modular construction allows many interior finishes to be factory-applied, which decreased toxic fumes on the worksite and greatly improves indoor air quality.