Northwood NH Masonry Heater
This heater features an air frame that the firebox door mounts to. This lets air flow into it at the bottom and is directed to the fire and also washes across the glass to help keep it clean. It was designed by Carsten Homstead of Homestead Heat. Other benefits of it is that it helps protect the brick facing around the opening from the extreme temperatures of the firebox. Air also feeds the fire through a grate in the firebox floor at the back.
Double bell masonry heater