The present research study includes thermal energy performance analysis of a flat platesolar collector, in order to cover a sensitivity analysis about effective variablescontributed to performance increasing approach. To obtain that, energy and momentumgoverning equations on a flat plate thermal collector were developed to achieve air outputtemperature and velocity profiles both in model and experiment. The model theory isvalidated with experiments by a set of flat plate thermal collectors, those located in(35◦44′35′′ N, 50◦57′25′′ E) coordinates and then were applied to carry outexperimental activities. Quantitative results depicted that the mean difference betweenpredicted and measured output air temperature in natural and forced convection scenarii is1.47 ◦C (3.5%) and0.9 ◦C (1.5%),respectively; however earlier research works and studies mentioned in literature, includeerror percentages in the range of 4–10%. Another quantification about, the average errorpercentages of estimated amounts of output air velocity profile values in natural andforced convection scenarii is 9% and 4%, respectively. This issue realizes the developedmodel in forced convection scenario more accurate than natural convection scenario.