Abstract: A low-cost energy-conserving system for heating and cooling the equipment and environment of a manufacturing installation, and more particularly, a printing plant, including an incinerator for burning waste paper generated as a result of the printing process, a first heat exchanger for utilizing exhaust gases from the incinerator for heating air to be supplied to a heat treating device or apparatus, and more particularly, a web press oven, first ductwork for conducting heated air from the first heat exchanger to the web press oven for heating purposes, second ductwork for conducting solvent-laden air from the web press oven to the incinerator where the solvents are burned to utilize their heating value and to also produce pollution-free gases, a second heat exchanger utilizing exhaust gases from the incinerator for heating air to be provided to the plant for environmental heating purposes, an outside air duct for providing air to be heated by the second heat exchanger, third ductwork for conducting heated air