With our summers getting hotter and winters colder, homeowners are constantly looking for ways to escape the extremes without running up higher bills.
The uptake of solar power systems is increasing exponentially, yet there are other ways to utilise the sun to make our homes more liveable.
Passive solar design refers to the use of the sun’s energy for the heating and cooling of living spaces through a regulated exposure to the sun. When sunlight strikes a building, the building materials can reflect, transmit, or absorb the solar radiation.
In addition, the heat produced by the sun causes air movement that can be predictable in well-designed spaces. These basic responses to solar heat mean that specific design elements, material choices, and placements can help keep the house cool in summer and warm in winter.
One major benefit is that the air conditioner, one of the most expensive appliances to run in the home and business during Australia’s hot summers and the prime driver of peak demand on days of extreme heat, can be sidelined to a large extent through sustainable design.
Here are the basic design elements for passive solar design:
– Materials with a high thermal mass, like stone, brick or rammed earth, take a long time to heat up and a long time to cool down.
– Walls with a high thermal mass should be shaded to minimise a heat load in summer.
– Glass is a very poor insulator. In an energy-efficient design think about the size, location, glazing type and window coverings like verandahs, canopies or planting deciduous trees.
– Consider locating windows away from the western sun, unless they can be shaded by deciduous trees in the summer. Likewise, utilise the eastern sun for winter warmth. Allowing the winter sun to shine on tiled flooring will ensure the retention of that heat for hours throughout the rest of the day.
– Site awnings, blinds and roof overhangs can be optimised to keep the summer sun off the house, yet allow the winter sun to strike at a different angle. Closing curtains and angling blinds will also reflect intense heat off the windows during summer helps keep the home cooler.
– Insulation is paramount to the energy-wise home experience. Lining the roof/ceiling, walls and floor can reduce heat loss in winter and heat-gain in summer.
– Cross ventilation is an important design factor, and entails providing at least two carefully placed and treated openings in every room.
– Louvres can direct the air flow towards the occupant of the room.
– High level windows can allow unpleasant hot air to escape, resulting in the drawing in of cool air.
– Reversible ceiling fans are great in summer and winter. In winter they push the warmed air down to where you are sitting. In summer they disperse the air around the room.
Demand for sustainable homes continues to lift, so one that optimises on all the benefits of our sunny climate – whether through solar panels to capture energy, batteries to store it, or clever design – will not only save its owners thousands of dollars on energy bills, but is also likely to gain value when it is sold.
