A flue shield and mesh baffle are described for use within HVAC systems and inside of a combustion chamber. The shield or baffle can be installed around the burner and within the combustion chamber to help dissipate heat that builds up as a result of the combustion of gas and air. An air gap is created between the flue shield and the inner surfaces of the combustion chamber and heat exchanger tubes. A mesh baffle can provide heat insulation and noise dampening. Installation of a flue shield or mesh baffle provides better efficiency than insulation solutions, reduces stresses on the heat exchanger, and provides safety benefits.