The present study investigates the effect of longitudinal wall conduction on the thermal performance of a direct-transfer type, single-pass, crossflow heat exchanger with nonuniform inlet temperatures. The exit mean temperatures and effectiveness with four kinds of arrangement that include longitudinal wall conduction are calculated by the numerical method. The capabilities of heat recovery with respect to four kinds of arrangements are compared, and a sequence of these four arrangements is displayed in terms of suitability. In addition, the wall conduction affects the thermal performance for each arrangement unfavorably, and the deterioration is affected by the parameters of NTU and nonuniform inlet temperature distribution.