Our wood and Coal furnaces are designed to heat your whole house much like your existing furnace. They are designed to be hooked into your existing ductwork to spread the heat evenly throughout your home. They can be used as a stand-alone product but are mostly installed as a primary heat source while using your existing heat source as a backup. These EPA exempt furnaces have large fireboxes and can handle logs up to 28 inches in length and are capable of heating up to 3000 sq. ft.