The HeatMaster SS MF20,000e outdoor wood furnace is capable of heating a large commercial shop, barn, or greenhouse. It is made of 409 titanium enhanced stainless steel, which has proven to be the best steel to use in an outdoor wood boiler. It had a round fire box to cut down on the number of welds and cause a hotter and more complete burn. This also eliminates corrosion from moisture in the bottom of a square fire box. It's unique rocker grates and removable ash pan make ash removable a breeze. The exhaust exits through a three pass heat exchange system, allowing it to make the same while burning up to 30% less wood than traditional outdoor wood stoves. Add stability to your budget and eliminate your heating bills with a good outdoor boiler today.