Yamaha EF2000iSv2 Gas Powered Portable Inverter is the best quiet generator available in the market. With features like centralized control, AC/DC output, and easier operations with auto decompression system, the product tops the list. It gets EPA and CARB Emission Engine Durability Rating. The mobile generator gets the muffler with the USFS approved spark arrestor to ensure less than 51.5 dbA sound. This is the quietest generator, too, besides being a highly efficient one in the market.