Convective and radiative heat fluxes enter simultaneously into most thermal engineering applications, especially in the vehicle underhood. However, separate measurements of these fluxes are needed for understanding and analyzing underhood aerothermal phenomena. In this context, a new experimental technique has been proposed (Khaled et al 2010 Meas. Sci. Technol. 21 025903) that allows the simultaneous measurement of convective and radiative heat fluxes. The technique uses a pair of fluxmeters with different radiative properties: the two fluxmeters measure the same convective flux but different radiative fluxes proportional to the fluxmeters' emissivities. This permits the separate calculation of the convective and radiative fluxes. This paper presents a sensitivity and applicability analysis of the new technique, taking into account the effects of a number of parameters such as emissivities, the precision of emissivity estimation and the difference in convective heat fluxes due to fluxmeter position. Also, new applications of this novel technique are proposed as an alternative when the initial version becomes inaccurate.