Passive Solar Design

Passive solar design is the art of designing a building that doesn’t need an active heating or cooling system such as expensive air-conditioning.

The heating and cooling is done by the building which is in harmony with and responsive to nature’s cycles.

There are proven health benefits to living in a passive solar building – Our body performs best and stays healthier when our living environment in tune with nature. When we artificially cool our homes and then go out into the summer heat, the shock can make us sick and in extreme cases even cause the death of older people.

Aside from the health benefits, passive solar design reduces our carbon footprint, we use far less energy and in doing so, help reduce greenhouse gases.

Using less energy also saves our hard earned money, which most of us can find better things to do with than pay unnecessary electricity bills.

When we produce a passive solar design, we focus on five major areas: The building’s orientation, shading and sun control, ventilation, thermal mass and Insulation.

Orientation is something that is often overlooked, but it is extremely important as it allows us to maximise the sun getting into the building during winter and minimise it during the summer. Nature works with us when the orientation is correct, simply because the sun is a lot lower in the sky during winter and can penetrate the building easier and a lot higher in the summer making it easier to keep the sun out.

Cross ventilation pathways designed into a building will enable you to make a good use of prevailing cooling Breezes in the summer.

The location and type of openings used is critical to make use of this basic cooling feature, also rising hot air is harnessed for both cooling and heating of the building.

Thermal mass such as concrete, water and masonry, all which are great materials for soaking up heat, can be used to great advantage in managing the heat cycle of a building in the summer. During summer, they will take heat out of the air during the day and release it at night when the building is in cooling mode. The reverse is true in winter when thermal mass is used to soak up heat from direct radiation during the day, storing it for the night time use when it is released to keep the building warm.

Insulation is utilized much more than it used to be, with the government now requiring it in building codes. Howeverit is not completely understood and a lot of the benefits are lost by incorrect installation.

Insulation of glazing is the most important aspect of passive solar design and very little is known about it in the building industry.The correct type of Glass and frame system is very important to prevent heat flow through the most vulnerable parts of the building envelope.

Sun control and shading for windows,and areas close to the building envelope is the most important aspect of passive solar design during summer. Once the sun has managed to get to the glass, half the battle is lost. Curtains on the inside of the glass are about as useful as an ashtray on a motorbike.

The real challenge is generally to maximize the sun getting through the glass and windows during Winter and minimise direct sunlight getting through the glass in summer. Correctly located deciduous shading greatly assists this principal.