Brise Soleil: What You Should Know?

brise_soleil on windows
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Have you ever wondered what are these louver-filled things on some buildings’ windows or facades? Do these things even serve a purpose? Or are they only for decorative purposes only? These things are called Brise Soleil.

Sounds fancy? Well yeah, but you’ll be amazed by the things that it could do for you and your house or building. So what are brise soleils? As an architectural feature, is it only functional? Or can it also be functional and decorative? Do you consider having it in your house or building?

Yeah. But, what is a Brise Soleil?

Brise soleil sounds fancy because it is a French term that literally means “sun breaker”. This architectural feature reduces heat gain or the heat that enters the building, especially during the hot summer months, where the sun is more intense. Brise soleil works by simply blocking sunlight, hence, the term sun breaker. The thing with a brise soleil is that it does not entirely block sunlight. Usually, it lets the morning sunlight enter the building but blocks the midday ones. It also allows air to flow through the building.

brise soleil on windows
Brise Soleil installed on windows. Photo Credit: Nationwide Louvre Company Ltd Flickr via Compfight cc

Brise soleils were popularized by modernist architect, Le Corbusier. It fits the very principle of modern architecture, that is, form follows function. For architects, especially the contemporary ones, consider brise soleil an important architectural feature, for it makes building facade more dynamic. Not to mention, a passive climate control element, a thing you need for a sustainable building.

Brise Soleil on Milwaukee Art Museum
Movable Brise Soleil on Milwaukee Art Museum. Photo Credit: Kenyan1970 Flickr via Compfight cc

So, what to consider if you want one?

The Climate

This is the primary consideration. Different climates have different temperatures because of the amount of sunlight they receive. Hot climates tend to receive more sunlight, so you would want to lessen the heat gain of your building. So brise soleil that will be built on this climate needs to have more angled slats with closer spacing between slats. It is recommended that you install windows that are facing the sun, so, it’s usually are the east and west-facing windows.

Cold climates receive less sunlight, especially in winter times. Here, you would want to have higher heat gain during winter times and lower heat gain during summer times. It is recommended to have a smaller brise soleil with less angled slats.

brise soleil on balcony
Airy Balcony

To make it short, you would want to lessen the heat gain of the building on hot climates and increase it on cold climates. 


This closely relates to climate. The earth’s spherical(yep, it is round) shape is the reason why different places on earth have different climates. Locations in high latitudes, that is, away from the equator, tend to have colder climates than the ones that are near the equator. The main factor here is the solar angle. 

Contemporary Vernacular Architecture-The Pebble House

So what is the solar angle? It is simply how high the sun gets when it rises on the horizon. As the noontime approaches, the solar angle increases to nearly 90 degrees. The thing is, the higher the angle of the sun at the horizon, the hotter the temperature becomes, and this is noticeable at noon times. Colder climates receive a lower solar angle than the hotter climates. 

Solar Angles. In point “a”, regions on high latitude receive less intense sunlight. The Solar angle is lesser. On another point “b”, regions on low latitude receive more intense sunlight. The solar angle hear is greater. Photo credits to, Peter Halasz, commons wikimedia.

Building Orientation

As a sun-blocking element, brise soleil installation depends on the building orientation. Building orientation is one consideration in building design, perhaps an important one. This roots from the universal fact that the sun rises on the east and sets on the west. Normally, we assume that the sun exactly rises on the east and sets on the west. 

But we have to keep in mind that this assumption is not exact. First, given the fact that the earth is round, different locations may have different positions where the sun rises or set. It still however does rise from east and sets on west, it’s just that some times it could rise slightly away from the east and so does with when it sets, slightly away from the west.

brise soleil

The season affects this too. For example, if you live in the northern hemisphere and its winter solstice, the sun rises further from the east and sets further from the west. (You can now easily know the sun’s position through NOAA Solar Calculator.)

Solar azimuth is the angle between true north and the direction where the sun is coming from. In some instance such as equinoxes, the sun directly rises from the east and sets direct on the west. Photo source, PV Education.


There are plenty of materials that can be used for building brise soleil. Wood and aluminum are the most common, but some use concrete. The use of concrete as a material for brise soleil was prominent in modernist designs, especially designs by Le Corbusier.

Wood has the advantage of being natural in terms of texture and feels. It’s just that it is heavy and needs more work. Plus, you have to check with your supplier for availability. Of course, it should be treated to protect it from fires and other elements for it to last very long.

Aluminum, on the other hand, is easier to produce and are lighter than wood. It may need minimal treatment, depending on the purpose. It is much preferred by builders because it’s easier to install. The downside is that it could be more expensive depending on the material availability and complexity of the design and they look unnatural.

Function plus Beauty

Brise soleil does not necessarily be functional, it can also be purely decorative. It can add dynamics to the seemingly bland facade, and the cool shadow effects on the building’s interior!

So, in conclusion, brise soleils are architectural elements than can add character to a building and also function as climate control. But before deciding on building and installing some, plan ahead. Consider practical design. Indeed, form follows function, but this does not mean beauty should be compromised.

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