Designing with the Sun!
The sun is a powerful friend!
It is a free renewable source of energy that, when harnessed correctly, can lead to a home that uses little to no energy to stay warm.
But, as with most things, too much of it can have negative outcomes!
If we fail to consider the sun’s impact in the design of a home, we could end up with a home that is extremely cold during winter and extremely hot during summer. A home like this would need to rely solely on an air conditioner to regulate internal temperatures and we could be subjecting a client to living in a home that receives no natural light.
And, as we know, getting natural light into our homes has significant impacts on our physical and mental wellbeing!
Designing with the sun in mind is a crucial first step in building an energy efficient home that is comfortable and healthy for the people living in it.
Here are 2 things I would do if I was starting out with a blank site…
Understand the site’s orientation: where is the sun coming from and how does it travel throughout the year in relation to the site?
Understanding the sun’s impact on the site gives us a huge advantage for the remainder of the projects lifecycle as it can help us implement solar passive design principles such as appropriate room and window placement, roof orientation (for a solar system) and utilising crossflow ventilation appropriately.
There are a few free resources that make this a breeze.
The first is a free SketchUp plugin called Curic Sun that I absolutely love.
Get it here: Extension | SketchUp Extension Warehouse
This plugin for SketchUp is fantastic.
To get a good understanding of the sun’s path over a site, set the sun at any time throughout the day and on any day during the year, for example Friday 20th of December at 3pm or, run a simulation that showcases a day from sunrise to sunset.
It is important to remember to review the June and December solstices and March and September equinoxes to have confidence that the design allows sun in during winter while controlling sun access during summer!
These moments in time showcase the longest and shortest days of the year (solstices) as well as when day and night are equal in length (equinoxes) which will provide important insight into how the sun impacts the site and how shading can start to be thought of.
To get detailed information on the times of the solstices and equinoxes for your site, check out this website: Equinox and Solstice Time in Adelaide – Equinoxes and Solstices Times – Timehubzone
Another resource that is handy, especially for any alteration or addition project is ShadeMap - Simulate sun shadows for any time and place on Earth
Find your site using the address search function and utilise the horizontal scroller at the bottom of the page to get a great understanding of how the sun travels over the site as well as highlighting any potential overshadowing from neighbours or nearby structures.
Room and window placement: Now that we know where the Sun is going to impact my design it's time for the placements of our rooms and windows.
Simply put, orientate:
Main living spaces North.
Bedrooms to the East.
Utilities (garage, laundries etc) to the South and West.
By doing this we allow morning sun to penetrate into the bedrooms and day-time sun to penetrate the living spaces while shading the harsh afternoon sun.
Western sun is the harshest and by minimising the amount of western sun we allow into the home we enable effective and natural cooling of the home in the afternoon on those especially hot summers days. By allowing the occupants to purge the heat trapped in their home throughout a hot afternoon, we minimise the amount of active cooling systems needed in a home. Ultimately this saves money in the long-run but it also creates a very comfortable living environment.
With the room locations in mind and shown below, windows follow a similar pattern.
Northern windows should be maximised but have effective shading during summer.
Eastern windows placed sparingly.
Western windows to be eliminated (as much as possible).
A simplified guide to orientating rooms and windows.
Of course, not every site is perfect, but by hitting some of these targets early we set up the project to have passive solar design act in the best interests of the occupant, both from a health and comfort perspective but also when viewing the homes specification and financial outcomes.