Pellet inserts must be vented vertically through the existing fireplace chimney. The existing chimney is used as a conduit for a 4” stainless steel liner. This liner is connected to the top of the insert, installed up the chimney and terminated with a special adapter and termination cap on top.
Note that many pellet inserts will be positioned a bit more forward on the hearth, compared to their gas or wood burning counterparts. A little extra space is needed to allow pellets to be easily poured into the insert’s storage bin or hopper.