Here are a few current pics from inside my coach to show what the ducting looks like. The lighted blue computer fan on the floor is sucking air out from the coach and pushing it through the piping in the heat battery. Denis and I took the sand out again last fall and converted the stove piping inside the heat battery to six inch thin wall steel pipe all welded together. It will be much more durable that way. I tried temperature testing the output in the coach one day. My thermometer maxed out at 160 degrees F and the numbers were climbing fast. I would guess at an output temperature of at least 180 degrees--maybe more! The last picture shows that I still use a couple of small infrared electric heaters to help with the heating in winter.The Aqua-hot will come on occasionally on very cold days. I can only heat exclusively with the heat battery in the spring or fall.