Interiors make up between three and five percent of a building’s total mass with heavy structural and envelope building systems accounting for the vast majority of materials and, therefore, embodied energy and environmental impacts. Over the entire lifetime of a building, however, its interiors are typically partially or completely replaced multiple times. The aggregate mass of a building’s interior materials over time can then rise to between ten to thirty percent of the whole. This material percentage of the total building material mass and attendant negative environmental impacts is worthy of the interior designer’s scrutiny and ecological optimization. New interior design focused LCA tools, coupled with measurably better performing products, aim to improve design and specification workflows for more sustainable interior product systems.