The Bosch flue gas heat exchanger reduces exhaust gas losses and enables effective heat recovery, which can reduce fuel consumption of industrial boilers by up to 7% - up to 14% with a downstream condensing heat exchanger. The system is compactly integrated at the boiler or available as a stand-alone version for easy retrofitting. Alternatively, feed water cooling or combustion air preheating offer further efficiency options. A sustainable solution for emission reduction and cost savings.