Sun shading or solar shading design is critical for creating a cooler tropical home. Direct sunlight shining on or in a home increases the temperature in the room. Adding sun or solar shading design strategies decreases heat gain. Hence, creating a home that is cooler and better thermally comfortable.
Today, solar shading devices are not as common in homes in tropical regions. More often, we see external sun-shading devices on commercial buildings. However, it is still a great idea to incorporate solar shading strategies into your home.
What Is Solar Shading?
Solar shading or sun shading uses elements to reduce or eliminate heat from the sun entering a building. Strategies for solar shading help protect openings and walls from direct sunlight. Therefore, it assists with controlling indoor temperature.
Why Is Sun Shading Important?
Direct sunlight on or in your home will affect its internal temperature. On walls, the heat from the sun warms the outer surfaces, and that heat can transfer to the inside. However, the impact is significantly higher when the sun’s rays enter your room through a glazed window or door.
This direct sunlight will increase the temperature of the room. Hence, you should try to avoid this condition in the tropics.
With glass windows or doors, the heat from the sun can easily pass through the glass. Once inside, that heat remains in the room. It is difficult for it to pass back out through the glass.
Thermal massing elements like concrete walls and floor slabs absorb the heat and radiate it back into the room. This situation creates warmer and more uncomfortable interiors in tropical climates.
This situation is also a problem with air-conditioned rooms. Doors and windows are usually closed. Hence the heat passes through the glass and heats your room. This heat increases the load on your air-conditioning unit to cool your space and, by extension, the electricity these AC units consume.
Effective sun shading devices reduce or eliminate the heat from entering your home or building by keeping direct sunlight out.
Sun Angles and Solar Shading Design for Tropical Regions
They are several ways sunlight impacts your windows and other parts of your home. These factors include the latitude of your location and site orientation. It also depends on the time of the day and year.
Therefore, be careful when researching the impact of the sun in your specific location. Many websites may give general information that relates to their particular region.
Any of these factors will determine the type and extent of the sun shading strategy.
East and West Facing Sun Shading
For example, the sun rises in the east and sets in the west. Because of this, the sun’s angle is low as it climbs up from or dips down to the horizon.
Therefore, vertical sun shading devices like fins, vertical louvres or even trees are more suitable. Horizontal sun shading will have little effect unless it is extremely deep and extends far from the house.
North and South Facing Sun Shading
However, the sun’s angle in the north and south is much higher. The closer you live to the equator, the more the sun will be close to directly overhead. However, it will also dip to the north and south at various times during the year.
Since the sun spends more time overhead, horizontal shading strategies are more effective. These strategies include roof overhangs and window hoods.
In addition, the sun’s angle will be lower on one side than the other. Again, this depends on the time of the year and your latitude.
For example, in countries north of the equator like Caribbean islands, Costa Rica, Hawaii, Philippines, Sri Lanka and India, the sun will be lower in the south than in the north. While in countries south of the equator like Brazil, Tanzania and Northern Australia, the sun will be lower in the north.
In temperate climates further away from the equator, the angle of the north and the south-facing sun is much lower. Also, the winter sun is lower than in the summer. Sometimes, you hear some persons speak about capturing that lower sun in the winter.
Significance Of Solar or Sun Shading Design In Tropical Climate
Passive design strategies use sun shading techniques. These techniques are helpful in both tropical and temperate climate regions.
In climates that experience winter, solar shading design strategies will usually block out the summer sun but allow the winter sun inside. This arrangement enables the sun to add warmth to a room during the year’s colder months.
Some homes in temperate regions will have significant glazed openings with little or no sun shading protection. They want the warmth of the sun to help heat their homes and hence, reduce the energy for mechanically heating.
However, homes need sun shading design to block direct sunlight all year in the tropics. Tropical climates tend never to get cool enough to require the sun’s warmth. Hence, all passive strategies usually aim to reduce the heat gain inside a house.
Therefore, having large glass windows and doors with no solar protection is not advisable.
How Does Sun Shading Design Work?
The light from the sun impacts openings in your home in different ways. The sun’s angle, as it relates to your house or building, depends on its geographical location, the time of day and the part of the year.
Sun shading techniques use vertical or horizontal elements to create a shadow over the openings for most of the day. The device should generate a shadow as much as possible as the sun tracks around the building.
The sun’s direction and angle will determine what type of shading strategy will be most effective.
On the north and south-facing glazed windows and doors, horizontal shades are better for shading direct sunlight from passing through the glass. The sunlight comes from the east and west in the mornings and evenings, respectively. Vertical solar shading devices are better in these locations.
How To Shade Your Windows From The Sun?
Shading your windows from direct sunlight is crucial in tropical climates.
Ideally, the sun shading device should be on the outside of the window. Shading devices inside a closed glass window will still allow heat to get in. These include curtains, blinds and interior plantation shutters.
Also, sun shading devices that still allow ample natural ventilation is ideal for tropical climates.
Horizontal solar shading on north and south-facing windows is typically fine since these do not tend to obstruct wind flow. However, vertical shading devices on east and west-facing openings should easily allow breezes. These could include vertical louvres or perforated screens like jalis and slatted timber.
Having operable sun-shading devices like moveable screens and shutters can also be helpful. You can move them out of the way when they do not need to shade your room from the sun. This condition allows for maximum ventilation or views.
Sun Shading Devices
Solar or sun shading devices are elements that protect your home but especially the window openings, from direct sunlight. These devices come in several forms and include manufactured elements like screens, canopies and roof overhangs. However, they can also involve natural elements like trees and vines.
Sun Shading Design Strategies
There are many design strategies to shade your home from direct sunlight. Different areas require different solutions and have various effects. Therefore, they are several different ways to do this, depending on the situation. These strategies can effectively reduce the heat in a house or building.
Here are some solar or sun shading design strategies that can be used in your tropical home.
Interior Curtains, Blinds and Shutters
One of the most common methods of blocking out sunlight from entering your home is using window curtains and blinds. When the evening sun starts coming through the window onto the furniture, television screen or the back of your head, you can immediately go and close the curtains or blinds.
Blackout blinds can also block out almost all light from passing through.
However, as much as they can block light from coming into the room, heat can still enter. If your glass window or door is closed, heat will pass through the glass from the outside. Once in, it cannot go back out.
Heat builds up on the inside of the window and permeates into your room. Hence, curtains, blinds or any screen inside a closed glazed opening will still allow heat into your room.
Similarly, plantation shutters that typically occur inside the window will still allow the heat to enter your home, keeping out some direct light.
In addition, if your window is open, curtains and blinds can impede some air movement through. This condition and their annoying flapping in the breeze do not make curtains or blinds an excellent option for keeping heat from the sun out while letting in natural ventilation.
However, they can be great for privacy and decor.
Roof Overhangs
Large roof overhangs can protect walls and window openings from direct sunlight.
This method is effective on the north and south-facing walls because of the sun’s angle. For those in the northern hemisphere, a wide enough overhang on the north wall can be sufficient to protect all the openings and walls of a single-storey building.
The overhang on the south walls will need to be wider according to how far away from the equator your location is. However, the reverse occurs in the southern hemisphere.
Veranda And Covered Patio
The roof of a patio or veranda can protect your interior spaces from direct sunlight.
They essentially have a similar effect to large overhangs but are much greater because of how far they extend from the wall.
Because of this, these can be more effective for south-facing walls and openings for persons in the northern hemisphere (the reverse for the southern hemisphere).
Because of how deep they are, covered patios and verandas can also provide additional protection to east and west-facing openings. However, once the sun gets to the lower angles, it could still penetrate your home.
Shade Sail And Fabric Canopies
Shade sail and other fabric canopies can also provide shade to an area outside your home. They often offer shade to a deck or patio. Hence, these shade sail canopies can help provide solar shading to glass doors leading to the deck.
Like verandas and covered patios, sun shading design strategies like these are most useful on north and south-facing openings. However, they can still be some sun protection on the east and west side because of how far they extend from the house.
Horizontal Window Sun Shading
A horizontal window shade device may be helpful in the absence of large roof overhangs or verandas.
Photo: Shamanth Patil J | House Of Voids | BetweenSpaces
Horizontal window shading devices can take many forms, including window hoods, cantilevering louvre, or slatted shades. These shading devices are more common in commercial projects than in homes. However, I am starting to see more options that suit residential projects.
Window Sun Shading Devices
In traditional vernacular architecture in many tropical regions, it was not uncommon to find window shading devices.
In Barbados, both low and high-income traditional houses carried hoods or awnings over the windows. They often had a bell shape and could provide some solar or sun shading and assist in keeping the rain off the window.
Unfortunately, we no longer see many window hoods for newer residences in the Caribbean or other regions. There are not a lot of contemporary applications of these available. The style of the traditional bell hoods is dated and hence unpopular.
Raised concrete bands and hoods and deep window recesses are more contemporary methods to consider.
Shutters
Like hoods, exterior window shutters were popular in traditional tropical architecture. But these have also lost their popularity in newer houses.
Fixed louvre and Bahama shutters, as well as Demerara windows, were typical in traditional houses. They could provide solar shading while allowing natural ventilation. These are rarely seen in contemporary homes now.
Screens
I am seeing more contemporary screens in modern tropical homes in some regions. Slatted and louvred sliding or bi-fold options are popular.
Photo: Grant Pitcher | Reserve House | Metropole Architects
They can be a good option for east and west-facing windows to respond to low sun angles.
These offer flexibility, as they can open completely when the sun is not on that side of the house. When the sun becomes a problem, you can close them while still allowing some natural ventilation.
Brise Soleil and Jalis
Brise soleil and jalis are great ways to shade a wall and glazed openings. They are essentially vertical perforated screens that tend not to move. However, they can provide shade while allowing for natural ventilation.
Brise soleil is French for sun breaker. They come in several different materials, styles and patterns and can protect entire facades of homes and buildings.
Photo: Shamanth Patil J | Cuckoo’s Nest | BetweenSpaces
A jali is more prevalent in Indian cultures. These are generally decorative and can be part of indoor screens and partitions. However, some types of jalis, like terracotta jalis, can shade interior spaces from direct sunlight. Because they both tend to be vertical sun shading systems, they are more effective on east and west-facing walls.
Trees And Vegetation
Trees, vines and other vegetation are another way to protect your home from solar heat gain.
I live next to an old traditional house that has been there for many years. It has many great responses to a tropical climate. These include window hoods, shutters, wrap-around verandas and steeply pitched roofs with ventilation blocks at the top.
However, large shady trees are on the east and west sides of that house.
In the late afternoon, the sun blazes through the west-facing windows in my living room. Even with the curtains partially closed, I can still feel the heat coming from that area.
However, practically the entire west-facing side of that house is in the shadow of those trees around the same time.
Photo: Hiroyuki Oki | Bamboo House | VTN Architects
Shady trees can be a great way to protect your home from direct light. They reduce the glare from entering your home and provide cooler areas outside. All this while permitting natural breezes to flow through.
Conclusion
Though exterior residential solar shading devices and strategies are not as common as in the past, I believe they are benefits to having these in your tropical home.
Preventing direct sunlight from entering your home is a significant aspect of tropical architecture. This strategy helps ensure that the indoor temperature remains as cool as possible.
Along with natural ventilation strategies, solar shading is an element you should consider when building a cool, comfortable home in the tropics.
Though popular, blinds and curtains are not as effective at keeping heating out of your room.
Large roof overhangs, verandas and horizontal shading devices protect the north and south-facing walls. They also allow for a free, uninterrupted window opening to allow maximum natural ventilation.
Shutters, screens and trees can help protect your home from direct sunlight on the east and west walls.
Solar or sun shading can be the piece of the puzzle for creating a home that is more thermally comfortable in tropical climates.
Photo by Jung Ho Park on Unsplash
Related topics in this series:
Find out all 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.