In a waste collection system where deposited waste is transported by partial vacuum in transport pipes (2) leading from spaced collection points to a central collection station (4) containing a system vacuum source (5) including at least one vacuum-producing machine (6), thermal energy is extracted from a vacuum-producing machine exhaust air stream (EAS), is transferred to a fluid medium and is used for heating or cooling purposes in a specific residential area where the deposited and transported waste is generated.