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