A systematic evaluation of the effects of velocity field and temperature field modeling on the calculations of turbulent heat transfer is carried out using a hierarchy of near-wall closures. Four different velocity field models are examined and they range from zero-equation to second-order models. In addition, three near-wall temperature field models are used to calculate turbulent heat transfer. These models include a constant turbulent Prandtl number model, a two-equation model and a second-order model for the normal heat flux. Different combination of these models are used to close the governing equations for channel flow with heat transfer subject to constant heat flux and constant temperature wall boundary conditions. The closures are examined for their ability to replicate the near-wall heat flux behavior. Furthermore, the effects of velocity field and temperature field modeling on the near-wall asymptotics are scrutinized and the relative merits of the different closures are discussed.