Abstract: In a burner assembly for location within an air supply housing for a heater and disposed for inducing the movement of air through a blower and into and around a burner assembly during heater operation to create a supply of heated air for a space to be warmed, the burner assembly being of the type having opposite side walls, and upper and lower tiered baffles forming a combustion chamber for reception and combustion of gas delivered from a gas manifold arranged approximately at the intake end of the burner assembly, a shroud arranged above and below the upper and lower tiered baffles, for directing air into an intake at the back of the gas manifold, and for diverting air through the baffles into the combustion chamber, a diverter arranged at the back end of the gas manifold for directing incoming air between the shroud and the tiered baffles, and a deflector arranged at the upper front of the top of the shroud, to delay the passage of air into the path of the combusting gases, with the sides of the combustion