“On a recent visit to a customer who uses his stove every day to cook, I was surprised to find for the first time the flue wasn’t coked up –  in fact there was less than half a cup full of soot. I asked him if he had stopped using the stove. “No” he said, “I still use it every day, but I have a new cowl.” I went outside to find a FlueCube on his chimney. “