Full feature article · Sustainable Homes
Solar Passive Home Design Ideas, Orientation and Photos
Orientation, glazing, thermal mass, insulation and cross ventilation — free comfort designed into the plan before a single system is bought.
Solar passive design is the cheapest performance available in a house, because it costs nothing to point rooms in the right direction. Living areas facing the sun, service rooms and garages on the cold or hot side, glazing sized and shaded for the orientation it faces, and a plan narrow enough that air can move through it. Get these right and mechanical heating and cooling become occasional rather than constant.
Glazing and shading work as a pair. Sun facing glass with an eave or louvre sized to admit low winter sun and exclude high summer sun delivers free heat exactly when it is wanted. West facing glass is the hardest to manage and the most likely to overheat a house, so it should be minimised, screened externally, or protected by a verandah. External shading beats internal blinds every time, because it stops the heat before it enters the room.
Thermal mass and insulation then hold the result. A concrete slab or masonry wall inside the insulated envelope, positioned where winter sun can reach it, absorbs warmth by day and releases it at night. Insulation to the roof, walls and slab edge, double glazing, and careful sealing of gaps around windows, downlights and doors reduce loss dramatically. Airtightness with controlled ventilation is what modern high performance homes do differently from older ones.
Ventilation and landscape finish it. Openings on opposite sides of every room for cross breeze, high level windows to purge hot air, ceiling fans in bedrooms, and deciduous trees positioned to shade the summer sun and drop leaves for winter. A vine covered pergola on the western wall does the same job cheaply. The photographs of these houses look calm and ordinary, which is the point: the performance lives in the plan, not in equipment on display.
