The environmental impact of solar farms, including photovoltaic and concentrated systems, has been the subject of extensive research. One critical parameter examined in these studies is total surface heat flux, which includes the summation of radiation and convectionat the panel's surface. A widely adopted method for measuring surface heat flux involves using direct-contact surface heat flux sensors. However, many of these studies overlook the radiation induced errors that lead to readings that underestimate the actual heat transfer. This problem cannot be simply addressed by adding radiation shielding to the sensor because doing so would block radiation heat flux, which is the actual source of heat one would want to measure. Hence, we designed this study to deliver a corrective equation to estimate and rectify this measurement error. Using data obtained from an experimental setup placed in the field, We computed how much an unshielded heat flux sensor underestimates the total heat flux. Using linear curve-fitting, we developed an equation that best describes the relation between this error and the incoming long-wave radiation.