A fireplace "insert" is intended to fit into a pre-existing masonry fireplace. I assume you mean a metal factory built "zero clearance" wood burning fireplace for new construction The wood burning fireplace "duct" you mention is a chimney whether it is masonry or metal. You can add gas to the firebox or put a gas log kit in it but the chimney must still be designed for a wood burning fireplace and sized for the fire box opening (unless you want to pay for it to be tested by UL). You need to either try harder to get the chimney offsets to work or use a metal factory built gas fireplace already tested by UL with a B-vent through the roof. Factory built gas fireplaces are made in two types: Direct vent and B-vent. The Direct Vent unit has a double-walled metal vent pipe that can terminate on an outside wall or through the roof. It is a closed system so the fireplace gets combustion air from outside through the outer wall of the vent and the firebox has a fixed glass enclosures. The B-vent unit has a single-walled vent that can only terminate through the roof. The fireplace takes combustion air from the room so it can be open to the room. Many of the units have folding glass doors. Carefully read the instruction for installing the vent. Consider an optional outside air supply duct to the firebox.

Everything said by akamaingrower is spot on except this: "I'm not sure what a fire starter pipe is, but if you mean a gas pipe, I'm pretty sure combining gas and wood burning in one fireplace would be a code violation, not to mention a very serious fire hazard." Gas starter pipes are the norm in most of the country; there's nothing illegal or hazardous about them. HOWEVER, you do need to make sure that the gas plumbing allows (heat can move back through the pipe if not plumbed properly) a simple switch to a starter pipe. You have a low-end pre-fab fireplace with a thin sheet metal firebox. You have a thinwall non-stainless air insulated chimney - these tend to rust the inner liner and cause problems. This will not be a good wood-burning fireplace. you can switch, but it's performance with wood won't be great. If you had a real masonry fireplace (with an appropriately high chimney) then the performance, safety, and durability would be much better; these are rarely installed by builders any more because the costs can be 10-50 times higher.

Greg here from Hansen Wholesale, where @tigerdunes purchased his ventless logs. I am also the one who has published all of the details at the Hansen Wholesale website regarding the pros and cons and differences between vented and ventless gas logs. Truth is, there are many considerations and we handle each case separately when dealing with our customers. In some cases, ventless makes sense, but in most cases vented gas logs are the best choice. The original thread here is 3 years old, but as I read the entire thread there is some confusion about welding the damper open when installing a direct vent gas log. I think Anapolitan may have confused "Vented" gas logs with a "Direct Vent Insert". There are no "Direct Vent Gas Logs". Direct vent refers to sealed metal box that you insert into the fireplace. There are two ducts that get run up the chimney with a special chimney cap installed at the top. One vent draws outside air down the chimney for combustion while the other is used for exhaust. It is an air tight sealed unit. Because there are 2 ducts, the damper would have to be propped open to feed the ducts up the chimney. Vented gas logs require that the damper is open when they are burning. Some municipalities may require you to weld the damper open when using a vented gas log. The reason vented logs need the damper open is because they burn more like real wood where they intentionally do not completely burn the gas. This creates a wafty yellow flame very much like real wood. It also produces Carbon Monoxide (lethal gas), Carbon Dioxide, Water Vapor and Soot. Hence the reason the damper needs to be open. With the damper open, most of the heat goes up the flue. Because ventless logs burn the gas completely, at least in an ideal situation, the byproducts are Carbon Dioxide and Water Vapor, neither of which present a health issue when used in moderation. Since the damper is closed, 99.99% of the heat produced by burning the gas will come into the room, so ventless gas logs produce a LOT of heat, sometimes too much. The R. H. Peterson ventless gas logs are rated as both vented and ventless. Technically, if they are intended to be used as vented logs the damper must be propped open permanently, but most people ignore that. The best solution to the issue of leaving the damper open all the time is to add a glass door to the fireplace so you can close the doors when the fire is off. Anyways, I have much more detail on our website and in the heads of our gas log experts. Anyone reading this may want to talk to us directly because each case really does need to be handled on an individual basis. Profided by: Greg Tillotson Hansen Wholesale: Gas Logs and Fireplace Doors Feel free to email me directly. If you do, be sure to include some pictures of your fireplace along with the inside dimensions: gregt@hansenwholesale.com P.S. If this comes through all in bold, I tried turning the bold off, but it wouldn't listen.

We have purchased Peterson Real Fyre gas burner and logs from Hansen Wholesale for our last two homes. The logs came with fluffy black material that looks like embers (I think its rock wool with shiny bits embedded), and various other items that made it look more real. I've seen other fireplaces that have an option for LED lights, which are apparently designed to look like flames and embers. Our last home already had a gas line run to the pref-fab wood burning fireplace (for a fire starter), so it was easy to connect the gas logs as a replacement. Our current house has an old wood burning masonry fireplace, and we had to pay a plumber to install the the new gas line and gas logs (including a city permit). Bruce