[jayco]

I use both coal and charcoal.

One problem with coal is finding good metalurgical or shop coal to use.
I live in coal country, and I can find coal pretty easily........but 99% of it had sulfur and other nasty stuff in it. In other words, it will burn and get iron hot, but it is smoky,creates a lot of cinder, and it takes me some effort to weld with it.

Charcoal makes a cleaner fire, but is more bulky.......it takes a larger pile of charcoal to make a forge fire comparable to a coal fire.

A charcoal fire seems to put out a lot more radiant heat than a smaller sized coal fire does.
Radiant heat in your face in hot summer weather can be downright uncomfortable .
On the other hand, that extra heat often feels good in winter!

If I use charcoal in hot weather, I place a piece of scrap sheetmetal over the fire to deflect some of the heat.

One handy trick you can do with charcoal is that if your coal fire is getting low(almost all your coke is burned up.......and you want to do just one more heat), is to throw a couple shovels of charcoal right on top of the fire.
You don't have place it around the edges of the forge and gradually rake it into the center like you have to with coal.

James