Method for controlling the blowing and/or cooling air flows of an I.S. glassware forming machine consisting at least of an air passage for the blowing and/or cooling air of a parison mold (1) and a blow mold (60) and air passages for the cooling air at least of the parison mold (1) and blow mold (60), wherein starting from a compressed air source, air flows are supplied at least to the parison mold (1) and the blow mold (60) in accordance with their intended purpose via different lines (12, 37, 48, 49, 64, 73, 80, 87, 105), characterized in that each cooling air flow is controlled on the basis of a volume flow of the cooling air, which passes through the cooling section of the glassware forming machine, in conjunction with the temperatures of the cooling air measured on the inlet side and outlet side in relation to the section, wherein the heat loss relating to the section is measured and wherein the volume flow is varied in accordance with a comparison of this loss with desired values.