One important vector for a sustainable growth of our planet is the air ventilation due to the large amounts of energy spent. When speaking about ventilation, the main thought is concerned with buildings. However, there is one more important sector, besides the building one, where a special attention is due: the refrigeration sector. The cooling of the outside air due to the air infiltration on refrigeration stores can consume also a large amount of energy. Read these notes carefully all the way through and follow them as precisely as possible. In this work several measurements were carried out on a common household refrigerator in order to find the air exchange rate trough the magnetic seal of the door. Tests were realized with a new and an old door seal. The main conclusion to withdraw is that the air infiltration rate on the refrigerator increases very fast as it becomes old, increasing in that way the energy consumption of the refrigerator.