@Terrificli -- I think that is true if you have charcoal with a lot of wood in it. Charcoal used for smoking, as I recall, isn't really a smokeless fuel because wood is put in to achieve that smoke flavor. I think that type of charcoal is very common.
Still, there are some brands of clean charcoal you can get and that is particularly useful if you are using it for heat. The long and short of all this is read the label on that charcoal and get exactly what you want.