The 7700 furnace is made with a firebrick lined steel firebox surrounded by a gray painted insulated steel cabinet. The unit features a full glass door to view the fire while in operation and can heat up to 3,000 square feet. The 1,800 CFM blower helps move the air to keep your heating costs down during the coldest temperatures.Up to 180,000 BTU's 26 Log length 1800 CFM blower Firebrick lined 6 Flue collarDepth: 43-1 2 Heating: Up to 3,000 sq. ft. Height: 48-1 2 Weight: 530 Width: 29-1 2