Abstract: A tent insulation liner which functions to both retain heat within the tent uring the winter heating season and reduce the external heat load during the summer air conditioning season. The liner is positioned on the interior side of an outer tent shell and is formed by alternating plies of fibrous flame retardant (FR) polyester batting, metallic reflective film and fibrous FR polyester batting and having fiberglass fabric as external cover layers. Optimum insulative properties were found to occur when a three-ply quilting arrangement was employed in which each fiberglass fabric layer was quilted to the adjacent FR batting layer and the two metallic film layers were quilted together with a FR batting layer between.