Outdoor Wood Furnace

My name is Ben and I have been in the outdoor wood-fired boiler industry for 12 years, ever since I saw one of these outdoor wood boilers heating a huge metal building with big garage doors opening all through a winter day; working on farm tractors.
What impressed me first was the lack of the sound of a furnace running. It was so quiet. I had to ask how they heated the building. I was surprised when they said it was heated with a Outdoor Wood-Fired Furnace that was outside of their building. I found out later that they were heating their domestic hot water for free, as well!