oliver power wrote:15' feet is the min recommended height for good draw. Then there's the 10 / 3 / 2 rule. Where the chimney needs to be 2 feet higher than any peak within a 10 foot diameter of the chimney. So now you have minimum Recommended height, and the 10-3-2 Rule. They are both guide lines towards a good chimney draw. With coal gasses not as hot as wood gasses, you'd want to shoot for 15'. The chimney height starts at the smoke outlet of the stove. I have a neighbor who has burnt wood for years. There chimney is only about 8 feet tall (trailer). A few years back, they tried coal, and hated it. Even with my coaching, they couldn't keep the fire going around the clock. (Being life time wood burner's didn't help any). From the start, I wondered if the short chimney was going to be enough for coal. Whether it was them, the chimney, or both, we'll never know. They sold the coal stove, and went back to burning wood. The hotter wood gasses created better draw in there short chimney.
what he said.
Bear in mind, 15' is a min. requirement and 10-2-3 rule has more to do w/ fire safety than proper draft. A stack should be a few feet taller than the highest part of the home's roof. People don't like to hear this because it might cost them more money or they have a tendency to think "good enough" or less will work "just fine". The problem is, it usually doesn't, especially in certain conditions such as mild weather, low stack temps, or unusual winds. Then they blame the stove in the house, the fuel, or God for their problems; If you're doing a chimney, do it right and exceed requirements to have good draft in most conditions.