A new and improved gas fired burner unit that can be utilized in applications where low emissions and high efficiency are desired including a burner body having a lower housing unit with a bottom portion, a distribution element located above the bottom portion, a burner deck located above the distribution element, and a metal fiber mesh element located above the burner deck. The burner deck supports the metal fiber mesh and spaces the metal fiber mesh from the internal distribution element to define a burner head. At least one inlet conduit communicates with the burner body and extends into the burner body to deliver a gas/air mixture to the burner body in a region located below the distribution element and above the bottom portion of the lower housing unit. The burner head has a permeability greater than 700 liters per hour, and the bottom portion of the lower housing unit includes a plurality of ribs providing added rigidity to the burner body and eliminating combustion noise.