Natural convection flows induced in vertical channels by heat sources situated at the channel inlet are considered. A channel plume is created by a horizontal line source, while a chimneylike flow is induced by a uniformly distributed source. Numerical solutions were carried out for both problems. Supplementary results were obtained from a fully developed model, which was further specialized for the case in which buoyancy effects dominate the frictional effects. Results were also adapted from available solutions for the classical free plume. For short, wide channels, the uniformly distributed source induces a larger mass flow than does a line source of the same strength, while for tall, narrow channels, the induced flows are equal. On the other hand, the bulk temperature rise associated with the uniform source is smaller than (or, in the limit, equal to) that associated with an equal-strength line source. Furthermore, for short, wide channels, the mass flow and bulk temperature results for the channel plume are in close agreement with the corresponding, properly interpreted results for the free plume.