An approach based on a new conceptual temperature termed the "equivalent ambient temperature" has been introduced for analyzing solar collector thermal performances when the environments to the front and rear of a collector are at different temperatures. Using a specially-designed solar simulator experimental work is presented which validates the new approach as applied to a wall-integrated covered profiled metal solar air collector Using both the new and traditional approaches, collector thermal performances are predicted to reveal the practical conditions for which use of the new approach is warranted. The latter findings will be of importance to designers. Performance characteristics for this collector geometry are also presented for use by designers.