The two most common options for outdoor shading are the pergola system and the bioclimatic system. In everyday Turkish the pergola system is sometimes spelled "pergole", but the correct word, of Italian origin, is "pergola". In this guide, aluminium pergola systems and bioclimatic systems are compared in terms of durability, resistance to weather conditions, and cost.
A pergola system consists of a fabric cover stretched over an aluminium supporting frame. The version where this fabric cover opens and closes on a rail with the help of a motor is called a pergola awning. Because the load-bearing body of the system is aluminium, it's quite durable, but since the top cover is fabric, it offers a different durability profile from a bioclimatic system. Aluminium pergola systems are frequently chosen for gardens, terraces, and cafés thanks to their low cost and easy installation.
The roof of a bioclimatic system is made of movable aluminium louvres. By changing the angle of the louvres, sunlight, air circulation, and protection from rain can all be controlled through a single system. Its key difference from a pergola system is that the top cover consists of movable aluminium panels rather than fabric.
The most vulnerable point of the pergola system is the fabric used as the top cover. Especially in pergola systems installed on the ground floor of buildings, cigarette butts and sharp objects thrown from upper floors can pierce the fabric. Even if the punctured fabric is welded and patched, this patch comes away after a while and the problem resurfaces. In a bioclimatic system, since the top cover is aluminium, there's no such risk of puncturing, and aluminium louvres are far more resistant to a falling sharp object than fabric. This is why, in ground-floor applications where there's a risk of objects falling from upper floors, the bioclimatic system is a safer choice.
When it comes to snow load, the difference between the two systems becomes even more pronounced. In bioclimatic systems, aluminium louvres are typically manufactured to carry a snow load of between 200 and 350 kg/m². This means the roof isn't damaged even if the louvres are left closed during snowfall. The pergola system is different. Because the fabric cover isn't designed to carry snow load, the fabric needs to be kept open and retracted during periods when heavy snow is expected. If the fabric is left extended, the snow accumulating on it can cause the system to collapse or the fabric to tear.
Wind is another important factor that should influence your choice of system. If a pergola system is going to be installed in a windy area, either all sides must be enclosed, or the fabric must be retracted as soon as a wind warning is received. If it's used with its surroundings open, or with 3 sides closed and 1 side open, the fabric in the system starts to behave like a sail, first billowing in the wind and then tearing away from the rails and detaching from the system.
In terms of initial investment cost, the pergola system is significantly more economical than the bioclimatic system. The square-metre price of a standard motorised pergola system is around a third of that of a bioclimatic system. The real source of this difference isn't the complexity of the system, but the amount of aluminium used. While a pergola system uses an average of 6-9 kilograms of aluminium per square metre, this figure can rise to 32-43 kilograms in a bioclimatic system. The exact amount varies depending on the size of the project, the span, and the structural requirements. If budget is your priority, and your space doesn't carry a risk of cigarette butts or sharp objects falling from above, and it's not in a region exposed to heavy snowfall and wind, the pergola system is an adequate and economical solution.
For gardens, terraces, or building façades in mild climates with no risk of objects falling from upper floors, the pergola system is a budget-friendly and adequate choice. In ground-floor spaces where there's a risk of cigarette butts or sharp objects falling from upper floors, the bioclimatic system is safer. In regions with heavy snowfall, the bioclimatic system is also more practical, since it doesn't require the fabric to be constantly retracted. Both systems provide many years of trouble-free service under the right conditions. The choice should be made based on the location, climate, and budget of the space.