Pellet Stoves Inserts - Convert Your Drafty Fireplace Into an Efficient Heating Source Pellet stoves are freestanding heat sources or fireplace inserts that install in your existing fireplace. They can be extremely efficient and burn compressed pellets that are made from wood byproducts like sawdust. They are also considered "green" https://www.fireplacesandstove.com/products/castle-serenity-pellet-stove-with-smart-control