Pellet Stoves Inserts - Convert Your Drafty Fireplace Into an Efficient Heating Source Pellet stoves can be free-standing heat sources or fireplace inserts that fit in your existing fireplace. They use compressed pellets that are made from wood byproducts, such as sawdust, and are extremely efficient. They are also "green" https://www.fireplacesandstove.com/categories/pellet-stoves