A fireplace liner comprising a first panel configured to be located in front of a fireplace burner assembly that has a lateral dimension that extends across a viewing window of a fireplace box. The first panel is configured to extend laterally along the lateral dimension, and, a rear end of the first panel, nearest to the burner assembly, includes a first trough having a vertical wall with a plurality of first slots therein. The liner comprises a second panel configured to be located behind the burner assembly in the box. The second panel is configured to extend laterally along the lateral dimension, and a front end of the second panel, nearest to the burner assembly, includes a second trough having another vertical wall with a plurality of second slots therein. The first and second slots permit secondary air flow there-through.