A coal forge needs a chimney to draw the smoke from the building. A well constructed chimney will remove all the smoke easily. Look for plans for any side draft forge for just one of the best options. For chimneys which have under optimum draw you can also add a fan
within the stack so that it will be a power exhaust for that smoke. This is effective.
Although a coal forge reaches higher temperatures, the heat is more concentrated. A properly constructed fire radiates hardly any heat into the room. A gas forge radiates a great deal of heat into a work shop. This is fine during the cold months but can be horrible in the summer time.
Many blacksmiths love the tradition of the coal forge. Lots of other blacksmiths have discovered the simplicity with the propane forge, and it is a great place to start or a versatile supplemental tool. Some blacksmiths utilize it as his or her main heat source for all their work.