Various implementations of the exponential wide band model (EWBM) are used to model radiative heat transfer in one- and two-dimensional enclosures containing CO2 and H2O. These are, first, the original banded approach using the four-region approximation for the total band absorption, second, a numerical integration of the spectral transmittance, and third, the wide band correlated k-distribution method (CKM). A correlated and a non-correlated formulation are used to solve the radiative transfer equation. In two-dimensional enclosures, these formulations are implemented using a ray tracing method (RTM) and the discrete ordinates method (DOM), respectively. The wide band CKM is found to be the best choice concerning accuracy and computational effort.