top of page
  • Writer's pictureLudovic Vilbert

Harnessing the Sun: The art of solar passive design

Welcome to our latest exploration into the principles of architecture, where today we are diving right into the heart of solar passive design with a focus on the sun's pivotal role.

Below, you will find a quote from one of the masters, accompanied by one of his paintings depicting the sun. This painting portrays the sun with a friendly face, while another suggests we need protection from it.

Le Corbusier: Medusa Soleil
“To introduce the sun is the new and most imperative duty of the architect.”

Le Corbusier in The Athens Charter 1933

The Sun: Our most valuable asset

In the heart of every home lies an untapped ally in our quest for comfort and sustainability—the sun, an ever-present source of light and warmth. At Inwardout Studio, we have always believed in the power of architecture that works with, not against, the environment. Drawing inspiration from nature's blueprint, we design spaces that are not just buildings but sanctuaries, harmonising with the earth and its rhythms.

The sun, a perpetual source of energy and light, offers more than just daylight. It is the cornerstone of solar passive design, a principle that guides our design ethos. It is not just about placing windows for the best view; it is about understanding the sun's path, the local climate, and how a building can optimise these elements for thermal comfort, energy efficiency, and a smaller carbon footprint.

Imagine a home that breathes with the seasons—cool and serene during the blistering summer heat, warm and inviting as the winter chill sets in. This vision is achievable through strategic orientation, thoughtful window placement, and materials that capture and store the sun's warmth or shield us from its excess.

Principles of passive solar design

  1. Orientation: The first step towards energy efficiency The journey to effective passive solar design begins with orientation. By thoughtfully positioning a building with its main windows facing north (in the southern hemisphere) or south (in the northern hemisphere), architects and building designers can capture optimal sunlight during the winter months, reducing the need for artificial heating. Similarly, incorporating eaves or other shading devices can block the harsh summer sun, keeping our homes naturally cooler.

  2. Thermal Mass: Nature’s temperature regulator Thermal mass is another cornerstone of solar passive design. Materials like concrete, brick, and stone can absorb and store heat from the sun during the day and release it slowly as temperatures drop, maintaining a stable indoor climate. Thoughtfully integrating thermal mass into floors and walls near sun-exposed areas can significantly reduce temperature fluctuations, enhancing comfort and reducing energy use.

  3. Insulation and Glazing: The invisible shields Effective insulation is paramount in passive design. It acts as a barrier, keeping warmth in during the winter and heat out during the summer. Similarly, high-performance glazing on windows can maximise natural light while minimising heat loss and gain. Together, insulation and glazing are the silent guardians of a building’s thermal comfort.

  4. Ventilation: Breathing life into buildings Strategic ventilation further embodies the essence of solar passive design. By encouraging natural air flow from cooler, shaded areas to warmer ones, buildings can effectively 'breathe'. This not only reduces the need for mechanical cooling but also improves air quality, creating healthier spaces for us to live and work.

In the illustration below, you can see one of our concept plans for a home in Tasmania indicating the sun's inclination at noon on the shortest day of the year in the southern hemisphere (21st of June).

House sustainable concept Inwardout Studio Tasmanai
Passive solar design principles

In the 3D renders below, you can see two of our design.

Adapting to Tasmania's latitude

An essential aspect of solar passive design is not just harnessing the sun's energy but also protecting our spaces from its excess. In Tasmania, located at a latitude of approximately 42 degrees south, understanding the sun's behaviour through the seasons is crucial for optimizing indoor comfort and energy efficiency.

Below, you can see a sun path related to one of our designs. The house allows the sun to enter, ensuring a cosy winter afternoon.

Sun path for the winter sun lounge extension in Tasmania by Inwardout Studio

Sun protection

In Tasmania's case, the angle of incidence—the angle at which the sun's rays hit the earth—varies significantly between summer and winter. To maximise solar gain in winter, when the sun is lower in the sky, windows should be oriented towards the north (in the Southern Hemisphere) and designed to capture the low-angled winter sun. Conversely, to minimise overheating in summer, when the sun is high in the sky, shading devices like eaves, pergolas, or deciduous trees can be strategically placed to block the high summer sun while still allowing winter sunlight to penetrate.

Calculating the perfect angle

In determining the optimal angles for window placement and shading devices for Tasmanian homes, it's crucial to accommodate the island's unique solar conditions, spanning latitudes 40°S to 43.5°S. The design goal is to achieve summer shade and winter sunlight according to the sun's varying path.

The angle of your timber slats or shading device should be tailored to the sun's path. A practical starting point for shading is aligning with the latitude angle, roughly 42 degrees south, to match Tasmania's position. This principle serves as a flexible guideline, suggesting initial angles for timber slats or shading devices but advising adjustments to suit the specific local environment and solar altitude variations throughout the year.

Embracing local latitude in design

By embracing Tasmania's unique latitude in our designs, we ensure that our homes and workplaces not only provide sanctuary from the elements but also leverage them to our advantage. This approach to solar passive design, tailored to the specific conditions of Tasmania, amplifies our commitment for creating spaces that are both sustainable and tuned to the natural environment.

Landscaping with the sun, food for the plants

At Inwardout Studio our focus does not stop at the building, we design all our landscape with the sun in mind. Calculating every corner of your block for the best outcome with your new plants.

Below, you can view the sun diagrams from some of our landscape projects. This is the first step we undertake when commencing a new job.

Sun diagrams for Sylvia’s Sanctuary, Hemp House garden and Perth Primary School by Inwardout Studio

As we continue to explore and implement solar passive design principles, we invite you to join us in celebrating the sun's power to create spaces that are not only energy efficient but also harmonious with the beautiful Tasmanian landscape. Let us embark on this journey together, designing homes that protect us from the elements while drawing strength from them.

Thank you for reading and I hope you enjoyed this blog post. Stay tuned for more!


Recent Posts

See All


bottom of page