I was asked today about installing a pellet fireplace insert into a direct vent gas fireplace. I dont have much info on the fireplace other than it was a propane direct vent unit installed in an alcove out the side of the house. This person was told by a Harmon dealer they could install as long as it was a zero clearance fireplace. I was surprised that it could be done. I would of figured not and then checked with the manufacturer of the insert. In the end they are leaning towards a pellet furnace hooked to their existing forced hot air duct-work and leaving the fireplace alone. Likely a wise choice as they wanted to heat the whole house not just one area. Just looking for input on this one for the future.