A calculationally efficient method of calculating time-averaged thermal radiation from flames is presented. The algorithm is derived by ensemble averaging the solution to the equation of radiative transfer. It is shown that, to a good approximation, the local power density can be decorrelated from factors that are functions of path averages. The ensemble averages of path-dependent functions can be calculated using time-averaged properties; the ensemble averages of the local power densities can be carried out by fast numerical quadratures using the local fluctuation probability density function. The result is a predictive technique that requires only one path integration per molecular band. The time-consuming approach of setting up statistical realizations of optical paths, calculating intensity for each realization, and building up the intensity fluctuation statistics is avoided. Sample calculations are given for a turbulent CH4-H2 diffusion flame.