As commercial buildings become increasingly energy efficient and glazed facades become more common, managing solar heat gain is an important consideration in building design.
Large areas of glazing can provide excellent natural light and attractive architectural finishes, but they can also allow significant amounts of solar radiation into a building. During warmer periods, this can contribute to overheating, increased cooling demand and uncomfortable internal temperatures.
External shading systems, including brise soleil and architectural louvres can provide an effective way of controlling solar gain before it reaches the glazing.
What is solar gain?
Solar gain occurs when solar radiation passes through a building’s windows and is absorbed by internal surfaces, increasing the temperature inside the building. The effect can be particularly noticeable with:
- Large areas of glazing
- South, east or west facing facades
- Highly occupied spaces
- Offices with extensive curtain walling
- Schools and educational buildings
- Healthcare facilities
- Commercial and public buildings
While mechanical cooling can help manage internal temperatures, reducing solar gain at the facade can help minimise the amount of heat entering the building in the first place.
How does external solar shading work?
External solar shading is positioned outside the building envelope to intercept solar radiation before it reaches the glazing.
This is an important distinction from internal blinds or shading. Once sunlight has passed through the glass much of its energy has already entered the building.
By positioning shading externally, solar radiation can be controlled at the facade, helping to reduce unwanted heat gain while still allowing natural daylight into the building.
The design of the shading system can be tailored according to factors like:
- Building orientation
- Window and facade design
- Glazing specification
- Solar exposure
- Required level of shading
- Architectural appearance
- Ventilation and maintenance requirements
Brise soleil as an architectural shading solution
Brise soleil is a popular form of external shading that combines solar control with architectural design.
Typically incorporating horizontal or vertical aluminium louvres, brise soleil systems can be designed to project from a building facade and provide shading to areas of glazing.
The orientation, spacing and angle of the louvres can be considered as part of the overall facade design, allowing the system to provide effective solar control while complementing the appearance of the building.
For architects and specifiers, this means solar shading does not necessarily have to be treated as an additional feature applied to a finished building. It can form an integral part of the facade design from the outset.
External louvres and solar control
Architectural louvres can also be used to provide solar shading while fulfilling other building requirements.
Depending on the application, louvre systems may be used for:
- Solar shading
- Natural ventilation
- Screening
- Acoustic applications
- Facade design
- Plant and equipment screening
This flexibility can make external louvres particularly useful on projects where several facade requirements need to be considered together.
For example, a project may require ventilation openings while also needing to control solar exposure. A suitably desiged louvre system can potentially address both requirements within the same facade system.
Can solar shading reduce cooling requirements?
Reducing the amount of solar heat entering the building can help reduce the cooling load placed on mechanical systems. The actual energy savings will depend on the building design and many other factors, including glazing specification, orientation, occupancy, ventilation and the buildings mechanical systems.
Solar shading should therefore be considered as one part of an overall energy-effeciency strategy, rather than a standalone solution.
When incorporated at an early design stage, external shading can be considered alongside glazing, ventilation, insulation and mechanical services to help create a more effective overall building strategy.
Solar shading and occupant comfort
Energy efficiency is only one consideration. Overheating and glare can also affect the comfort and usability of occupied spaces. Offices, classrooms and other commercial environments with extensive glazing can experience uncomfortable levels of solar exposure at certain times of the day.
External shading can help control direct sunlight and solar gain while retaining the benefits of natural daylight. For buildings where occupant comfort is particularly importan, considering solar constrol during the early stages of design can help avoid having to retrofit solutions later on.
Brise Soleil vs external louvres: which is right for your project?
There isn’t a single solar shading solution that will suit every building.
Brise soleil can be particularly effective where architectural solar shading is a key consideration and the system needs to form an integral part of the buildings facade.
External louvres can provide greater flexibility where solar shading needs to be considered alongside ventilation, screening or other facade requirements.
The most appropriate solution will depend on the individual project. Factors like building orientation, glazing area, facade design, solar exposure and the desired architectural appearance should all be considered.
Consider solar shading at the design stage
One of the most effective ways to approach solar shading is to consider it before the building is constructed, rather than treating overheating as a problem to be solved later.
For architects, engineers and contractors, early consideration allows the shading system to be integrated into the facade design and coordinated with other building elements.
It also provides the opportunity to consider the relationship between solar control, natural daylight, ventilation, occupant comfort and energy performance.
Bespoke solar shading solutions from TEK
At TEK, we manufacture high quality louvre and solar shading solutions for commercial and architectural applications.
Our systems can be designed to meet the requirements of individual projects, with technical support available to help architects, specifiers and contractors identify an appropriate solution.
Whether you’re considering brise soleil, archictural louvres or external solar shading, our team can discuss your project requirements and provide guidance on the options available.
