The second way of energy losses of buildings is through convection, or simplified, the unwanted and uncontrolled air mixture inside-outside. (Air Leakage, or leakage of air).
Hence, the importance of the airtightness of the buildings envelope (façade elements, roof and to the ground) is very high, but in the region it is the neglected part of the measures for achieving energy efficiency and high comfort in buildings. In the high parts of the building, the hot air exits through cracks, and in order to maintain the balance of air in the building, cold and polluted air is withdrawn from the lower levels. In the summer period, the mechanism is reversed. But not only air, even insects and rodents enter the building through such cracks.
It is important to know that the overwhelming, as well as too little congestion of a building brings big problems with it. For energy efficient buildings with standard heating and cooling systems (without ventilation systems), the air permeability should be n50 = 2h-1 to 3h-1. For large structures and for buildings with ventilation systems, completely different values apply. Therefore, this issue should be left to professionals.
Energy losses caused by uncontrolled leaks can reach up to 30% of total energy losses, making solving of this problem a very important element of energy efficiency. The heating and cooling costs will be seriously reduced by preventing uncontrolled mixing of internal with outside air while all windows and doors are closed, i.e. by achieving greater sealing of the buildings shell. Various invisible "holes" through which air flows (Air Leakage) through walls and the roof, as well through and around windows and doors, are the cause of drafts, mold, moisture and condensation in amounts that often leads to the delusion that the flows are through the roof or through the windows.
The experience from tens of thousands examined facilities suggests that only 1% of the buildings can be rated as super-hermetic, about 5% as satisfactory, 10% as acceptable and even 85% do not meet the basic criteria for airtightness. For buildings with high altitudes and large volume facilities (shopping malls, warehouses, production halls, etc.), the problems and losses of energy caused by poor sealing are several times bigger. In such facilities, good sealing between floors or between separate parts of the building is of great importance.
Airtightness is especially important in buildings that use ventilation, heating and cooling systems. In these buildings, insufficient sealing results in uneconomic and overloaded systems, high energy costs, costs for repair and maintenance of systems, and often, despite this, it is not possible to achieve the desired temperatures and comfort. With small interventions and costs, the gain in such facilities can be huge.
Airtightness is controlled and measured with the so-called Blower Door Test, and the weak spots, holes, cracks, windows that do not seal and other faults in the building envelope are diagnosed with Air Leakage Inspection. These measurements and tests are carried out with sophisticated equipment and CIVKON AGI is providing it to the customers.