Abstract: Heating apparatus, typically for providing domestic central heating and hot water supply, comprises a gas or other fuel burner (13), a flue (16) extending from the burner to an outlet, a first chamber (21) operatively carrying a first body of medium, e.g. water, heated directly from an upstream zone of the flue utilized typically as the boiler of a central heating system, and a second chamber (10) operatively carrying a second body of medium, e.g. water, heated directly from a downstream zone of the flue and preferably also by indirect transfer of heat from the first chamber with which the second chamber may be in surrounding relationship, the latter chamber typically serving as the hot water cylinder for the domestic hot water supply.