Metal façade gratings as passive sunshades: smart design for a cooler and more sustainable building

1. How does a ventilated façade with metal gratings work?

In a traditional façade, solar radiation is absorbed directly by the exterior wall or façade cladding. Materials such as concrete, brick, and natural stone store this heat and slowly release it throughout the day and into the evening. This phenomenon, also known as thermal mass, causes buildings to continue releasing heat into the interior even after sunset.

Placing metal gratings screens, expanded metal, or other open-mesh structures in front of the façade creates a ventilated air cavity. The mechanism is simple yet highly effective: a large portion of direct solar radiation is intercepted, while a natural airflow is generated behind the gratings. Warmed air rises and is continuously exhausted—the so-called chimney effect. As a result, the façade behind the gratings remains significantly cooler, and less heat is stored in the structure.

The result is a building that absorbs less heat, which in turn reduces the building’s cooling demand.

2. Lower cooling demand and greater comfort

For modern non-residential buildings, cooling often accounts for a large portion of energy consumption. Offices, educational institutions, healthcare facilities, distribution centers, and industrial buildings, in particular, experience high internal temperatures during hot periods.

By limiting heat gain through the facade, the cooling load on HVAC systems is reduced, and peak temperatures can be lowered. This ensures a more stable indoor climate and improves thermal comfort for occupants, while energy consumption decreases during the summer months.

For buildings with large glass surfaces, a combination of façade gratings and exterior sunshades can also provide even better control of the heat load.

3. Virtually maintenance-free and long-lasting

Unlike traditional sunshades, metal façade gratings contain no moving parts. This makes them exceptionally low-maintenance and resistant to harsh weather conditions.

Depending on the choice of material—such as steel, hot-dip galvanized steel, aluminum, or stainless steel—these systems offer a long service life and high corrosion resistance. They retain their dimensional stability, require minimal maintenance, and are fully recyclable at the end of their service life. As a result, metal façade gratings represent a sustainable investment with a low Total Cost of Ownership (TCO).

4. Architectural freedom

Façade gratings have long since ceased to be purely functional products. They are increasingly used as defining architectural elements. By varying the slat orientation, opening percentage, depth, perforation pattern, material, and color or powder coating, virtually any desired aesthetic can be achieved—from an industrial look to a high-end façade with clean, sleek lines.

In addition, utility systems, parking garages, mechanical rooms, and ventilation openings can be elegantly concealed behind the façade without compromising necessary ventilation.

5. More than just sun protection

In addition to reducing the heat load, metal façade gratings offer various additional benefits:

• Natural ventilation: The open structure allows for natural ventilation without the need for large, open façade openings.
• Facade protection: The underlying façade is protected from direct UV radiation, rain, and weather conditions, allowing materials to retain their appearance longer.
• Privacy and screening: Depending on the chosen open area percentage, utilities, mechanical rooms, and parking garages can be concealed from view while maintaining ventilation.
• Maintaining light penetration: Unlike solid façade cladding, louvre systems allow diffuse daylight to pass through. This keeps the façade appearing light and transparent.
• Circular construction: Metal gratings are ideally suited for circular construction concepts. They can be installed in a removable manner, are fully recyclable, and can often be reused in future projects.