When building a new home, site orientation is critical. The orientation of your home on its site dictates how well it responds to passive design principles. These principles determine the thermal comfort of your home and its energy efficiency.
In general, the site orientation of a home can be based on several factors. Some of these include taking advantage of views, protecting from noise or providing adequate privacy from neighbours.
However, in the tropics, they are specific principles to consider. These relate to the solar heat gain and natural ventilation of your home.
The sun and wind move across the site of your home in different ways. Depending on your geographical location and the time of the year, the sun’s path and the direction of the wind can come from different directions. Your home’s site orientation, along with passive design strategies, will help determine how direct sunlight and wind impacts your home. The location and function of your rooms as well as how your window openings are located are all considered when determining the site orientation of your home.
Here are two main climatic considerations when orienting your home on a site in the tropics.
1. Minimise Solar Heat Gain
In tropical climates, it is important to minimise the amount of direct sunlight that enters your home. Direct sunlight can significantly increase your indoor temperature. Also, it can cause thermal massing elements like concrete floors and walls to absorb the heat from the sun and release it into your home. Even after sunset.
Depending on your geographical location determines the angle of the sun on your site and home. For us north of the equator, the sun’s path is lower in the south than in the north, depending on the time of the year. Hence, during the middle of the day, you should shade the openings on these walls adequately.
East and especially west-facing walls experience the most intense solar exposure. This is because of the angle of the sun in the morning and evening, respectively. Openings on these walls are harder to shade. However, you should shade openings in these locations with vertical screens, shutters or trees to reduce solar heat gain.
Use relevant solar shading strategies depending on the site orientation of your home and the direction each wall faces. Elements such as roof overhangs and horizontal window shading devices are great for north and south-facing walls. Shutters, screens and trees may be more useful on east and west-facing walls, provided they do not obstruct airflow.
Also, position verandas and covered patios to provide shading to interior spaces. They, as well as shady trees, can also cool the exterior areas and surfaces around your home. This will cool the air coming into your home, making it more comfortable.
Where possible, it would be ideal for shading all walls all year round. Especially walls with a high thermal mass like concrete.
2. Maximise Natural Ventilation
The other major aspect when orienting your home is natural ventilation. In the tropics, having adequate natural ventilation will determine how comfortable you and your family will be.
Orient your home so that your windows face prevailing winds.
In the Caribbean, our prevailing winds come generally from the east. Prioritise the rooms that require the most ventilation and position them towards the prevailing winds. Typically in Barbados, we orient our bedrooms towards the east to take advantage of the breezes. However, all or as many of your rooms as possible should receive adequate natural ventilation.
Homes should also be designed and oriented to encourage cross ventilation. This means creating narrow, unobstructed pathways through your home for the wind to flow from one end to the other.
Also, select windows depending on the direction they face as well. These can assist with redirecting airflow into your home or minimising the amount of rain that comes in.
Conclusion
Site orientation has great climatic implications on your home. It is far more than taking advantage of views or creating privacy.
Orient your home so that you can shade walls and window openings adequately. This strategy would prevent direct sunlight from entering your home. Where possible avoid direct sun coming into contact with your thermal mass walls.
It should also encourage maximum airflow movement in and through your home so that you and your family are always cool and comfortable.
Good site orientation is a critical design strategy for creating your home in the tropics.
Featured image by Tito Rebellious on Unsplash
Related topics in this series:
Find all of the major principles of designing a house in the tropics.
Or explore more of the other topics in this series.
Site Orientation: The orientation of your home on its site dictates how well it responds to passive design principles.
Shading Strategies: Reducing the solar heat gain in your home can create a better thermally comfortable home.
Passive Ventilation: Natural or passive ventilation is one of the primary concerns of a tropical home.
Wall Materials and Construction: In hot, humid climates, your wall materials need to perform various functions.
Roof Design: Choosing the right roof in hot tropical climates is essential to minimize heat gain.
Exterior Spaces: Making outdoor spaces and nature part of tropical homes is ideal.
Water and Energy Efficiency: With climate change, renewable energy and water resource management are crucial.
Hi Hugh. I recently came across your website when I was looking at your article on Jalousie windows and I absolutely appreciated the content. I am an engineer/architect as well with a background in internal environmental design, so your blogs are useful in the Caribbean context. I am from St. Kitts and Nevis.
Now in terms of shading on the east and west, I’ve seen other articles and posts on the advantages of egg-shell shading in these directions. Is that something you’d recommend to a client?
Hi Dillon, Thanks for reaching out. I am happy you find the content useful.
An egg-crate shading device should be able to work. Since these have a vertical element, they can help protect from the east and west-facing sun. However, it depends on the depth and spacing of the device’s vertical blades/fins. Feel free to email me the type of egg-crate shading device design you have in mind, and I would be happy to share my thoughts. hholder@architropics.com.