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.

According to Charles E. Beck, P.E., Seattle Every motor has to have a disconnecting means, and the disconnect has to be within sight of the motor location. Reference NEC 430.102(B). So you can only take credit for the breaker at the main panel as being the disconnecting means if that breaker is within sight of the motor location, and is cabable of being locked open. That said, I don't think the manufacturer of a motor is required to provide the disconnecting means. It can be furnished and installed by the electrical contractor. My electrician says it is only required if the blower is direct wired and the code falls under motor disconnect. So I guess that makes it officially required by the national electrical code.

I have a Fireplace Xtrodinaire FPX44 wood burning insert that I use as my backup heat source. Not only does it look nice, it can generate a massive amount of heat. I have had to learn how to make small fires and control the burn rate when we want a little ambiance versus backup heat mode where we need to crank it. The one caution about the FPX 44, or any fireplace like this, is you need to check the venting requirements. This unit requires two input vents for combustion plus a third input vent to draw in and heat fresh air from outside - and they have special placement requirements. It might be difficult to make all this venting work with your existing chimney. I would also check the flue requirements - how far will it need to stick out above the top of the chimney stack. The flue for my unit is large - I think a 16 inch diameter pipe, and the cap is even larger. My firplace is at the back of the house so you cannot see the large cap from the front. With your chimney in front, it might not look right to have a large silver dome sticking out from the top of the chimney. They make a smaller FPX wood insert, but I am not sure if the flue is any smaller. I can vouch for the heating and efficiency of the FPX insert. After a 12 hour burn, I wind up with about 1/2 of a 3 gallon pail of ashes. You could easily heat your house with this unit. Distributing all that heat will need to be thought out. When I start this thing up, I turn on my 1st floor and 2nd floor HVAC fans to draw heat around the house to keep the rooms near the firplace from getting too warm. The first time I cranked it without turning on the hVAC fans, I raisied the temperture in my family room-kitchen-dining room space from 65 to 77 in about 30 minutes! When I go into backup heat mode, I plan to use free standing vans to circulate the warm air around the main level of the house. If you plan on using an insert or firebox that has a fan in it, I recommend looking into a backup generator (a small portable unit will do just fine) so that you can operate your fireplace, plus any of the distribution fans, if the power goes out. The FPX unit can we operted without power, but the radiated heat generated stays fairly local to the unit - you really need the fan on to push the heat around.

At least some! Perhaps a blower so that the BTU's actually come into the space v. traveling up the front? Or, perhaps tell us that this is for decoration only and suggest alternatives...like the heaters we eliminated in favor of the fireplace? These heaters seem to work in an open air environment; why not a fireplace? I am obviously not a thermal expert but I appreciate your comments. Thank you.