The ECO-55 has a hopper capacity of 80 pounds with a burn time of 69 hours. The unit can easily heat areas as large as 2000 Sq. Ft. Large window measures 15-3/4 In. x 8-1/8 In. The unit is approved for mobile homes and alcove installations; qualifies for the 30% Federal Tax Credit. EPA 2020 approved - Certifications: CSA B415.1-10, EPA, ASTM E2779, ULC S627, UL 1482, ASTM E1509.