Abstract: A space heater for small rooms, e.g. house trailers or ship's cabins, comprises an undulating heat exchanger centered on a vertical axis and a combustion pipe surrounded thereby. A burner enters the lower end of the combination pipe whose upper end is closed except for a number of lateral openings communicating with outwardly closed smoke channels of the undulating heat exchanger which alternate with outwardly open air channels. An outer peripheral wall, spacedly surrounding the heat exchanger, forms with its air channels an annular conduit for the conveyance of ambient air entering that conduit near its bottom and leaving it at its top.

Abstract: A space heater for small compartments in which the burner is received in an upwardly open tray bottom which has an outwardly extending flange connected to an outwardly extending flange at the lower end of the combustion chamber. The tray has a lateral opening for the combustion air thereby eliminating the need to go through the floor with a pipe forming a combustion air intake.

Abstract: A water heater has a closed container of approximately circular cross-section, a housing surrounding at least a lower part of the water container, the housing being closed by a base and forming, with the base of the water container, a gas-tight combustion chamber, a lower induction aperture for fresh air, an upper extraction aperture for waste gases, and passages through the water container for inlet and outlet pipes. The improvement is that an annular space connected with the combustion chamber is formed between the housing and the water container. The waste gas extraction aperture and the fresh air induction aperture are located in the housing. One or two box-shaped corner sections, for one or both apertures, adjoin the curved housing and, by means of their side walls, convert the housing in the vicinity of the corner sections into a rectangular shape. A connecting branch to link up with a through-flow unit in the outer wall is provided in one side wall.