Abstract: The invention relates to a method for treating products with air in order to enable the conservation, storage and use thereof. Said invention also relates to a device for treating such products and the products obtained using said treatment method. The products (P) to be treated, such as a hay drier or other similar agricultural products, are loaded into a closed space (20) that is connected to a thermodynamic machine (21) which is controlled using a programmable automaton (22) and which is powered by an electrical cabinet (25). Three mass of water in air sensors (Q1, Q2 and Q3) determine the operation of the machine according to the desired treatment objectives both in terms of moisture in relation to the product treated and power consumption. The invention is suitable for treating diverse products such as agricultural products.