At Washington RetroFoam, we insulate the walls of existing homes. About half the homes in the Pacific Northwest over 40 years old have no insulation in their walls. Others have highly degraded insulation. We use a foam that is harmless to touch, non-volatile, and Class One Fire Rated. We can typically insulate a 2,000-square-foot home in less than five hours for less than $4,900, usually driving a payback in less than three years.