A burner assembly for a fuel-fired heating appliance that defines a direction of flow of a fuel and air mixture in a flow path. The burner assembly comprises a plurality burners defined in a unitary mesh structure. Each burner defines at least one peak at a distal end thereof in a direction of flow of a fuel and air mixture. The burner assembly also comprises a diffuser plate having a plurality of perforated areas defined therein and one or more imperforate areas between respective perforated areas of the plurality of perforated areas. The perforated areas respectively correspond to the plurality of burners. The diffuser plate is disposed in a fixed position upstream of the mesh structure so that, when the burner assembly is disposed in the flow path, a respective flow of the fuel and air mixture is directed from each of the plurality of perforated areas to its corresponding burner of the plurality of burners.