Passive Solar Design Principles

We have discussed the benefits of Passive Design on the blog in the past but for those of you who may have forgotten, Passive Design refers to a design approach ‘that takes advantage of the climate to maintain a comfortable temperature range in the home.’ Thus, Passive Solar Design refers to the use of the sun’s energy for the heating and cooling of these living spaces.

Why passive solar?

With our energy consumption skyrocketing, there is no denying the importance of passive design in our built environment. Not only will the introduction of the right passive design principles make our homes more comfortable but we will also see significant financial and environmental benefits come as a result.

For many people the idea of Passive Solar Design sounds great, ‘I would love solar but I can’t afford it’ they so often say. And while we endorse the use of solar panels, it is important to remember that the true genius of Passive Solar Design is found in the word ‘Passive’. The ‘Passive’ solar gain and heat control of our homes comes as a result of our environment and the orientation, insulation, ventilation and thermal mass implemented through good design, not necessarily the latest technology.

So, what is passive solar heating and cooling?

Basically, passive solar heating is all about keeping out the summer sun and letting in the winter sun, whereas Passive cooling refers to elements such as air movement, evaporative cooling and thermal mass and their ability to cool a home.

Passive Solar Design is best achieved through a careful planning process, preferably one involving an architect, designer or industry professional. While it is far easier to implement Passive Solar Design measures before construction, it is also important to remember than renovations or simple home improvements can be made.

When considering Passive Solar Design it is important to address the following principles:

How to Design for your climate?

By identifying the climate zone of your particular site you will gain a far better insight into which principles of thermal control will need to be introduced. For example, a heritage home in Brunswick will require far different passive solar design features than a Shoreham beach house. (Remember: The Nationwide House Energy Rating Scheme (NatHERS) that we featured last week is a great way to evaluate your site’s climate.)

Orientation

Good orientation (especially when combined with other energy efficiency features) can significantly reduce or even eliminate the need for auxiliary heating and cooling in our homes. Often times we use the sun as a source of free home heating by letting winter sun in and keeping unwanted summer sun out.
Luckily in Australia, it is relatively easy to orientate our homes for passive heating on northern elevations by using horizontal shading devices to exclude high angle summer sun and admit low angle winter sun.

Shading

Effective window or glass shading is one of the cheapest ways to reduce unwanted heat loss. Shading systems such as eaves for example can block up to 90% of our homes’ heat loss.

So if you’re interested in saving some money on this winter’s electricity bills, saving the planet and making your home just that bit warmer, we suggest giving Passive Solar Design a chance, or at least evaluating the energy star rating of your home, it might just give you the incentive to make some structural or simple changes.