The generator, installed, with the lid of the compartment finished and in place. The suggests 2\" is provided--barely. The lid itself is a sandwich of sheet metal, a half-inch of duct insulation, and a half inch of plywood. You can hear the generator inside, but the cushions on the settee will help. It\'s certainly no louder than the Onan. Note to those who buy the Generac: You can start and run the engine without the inverter/controller being installed.