A heater, for an incubator for infants, has a housing structure with an upper housing surface and a lower housing surface, at least one air inlet for an inflowing air stream, at least one air outlet for an outflowing air stream, at least one fan impeller, at least one heating element and at least one heat transfer element. The upper housing surface and the lower housing surface delimit a flow space. The heat transfer element is a plate with a flat surface that is arranged horizontally during operation of the heater. An incubator for infants having such a heater is also provided.