As a matter of fact we did some testing. I was able to bring about 3 cups of water to a rolling boil in what should have been about 11 minutes. But, I let the fire down a little too much before putting in some more sticks and I had to get it going again. It wasn't too difficult since there was still some coals in there. The one thing that I did make when I got back home was a 'blowtube' to put air more directly into the stove without getting my face close to blow in the holes. I made it from a piece of fuel line hose and 3/32" copper tubing I picked up at the hardware store. About 14 inches of hose and 2 inches of tubing work real well to keep my face away from the heat and smoke. The copper tubing keeps the hose from melting. The whole thing coils up and fits around the stove (after cooling
) and in my cook pot.
I saw this on Survivor man so it's not my idea.
Hope this helps.