These dual systems meet all the requirements for firewood and pellet fuels in two separate combustion chambers in the convenience of one unit with single flue. Highly efficient and highly convenient. The firewood can be automatically lit at any time using the pellet burner and once the firewood has burned down, the system automatically switches to pellet operation. With variants 15 and 20kW in a compact version and 22 to 48kW (40kW Pellet) in standard size.