The Hot Blast HB1520 by US Stove is a wood burning furnace designed to use in conjunction with your existing HVAC ductwork. With twin 500 CFM blowers and up to 180,000 BTUs, it is designed to heat a home up to 3,500 Sq. Ft. Its heavy duty cast-iron door with a glass viewing front gives out the ambience of a flame without compromising efficiency. The open plenum allows for easy installation and with a built in ash-pan and firebrick line combustion chamber, the HB1520 is a great option for heating larger spaces in the furnace category. The Hot Blast HB1520 EPA certified furnace exceeds 75% efficiency.