I would take the dimensions of the fireplace to a dealer and ask then which models would fit your situation. If possible I would spend the money and get a good unit, Jotul makes a great product. Also have the combustion air hookup installed, you'll never regret it. A dealer can also tell you what. if any' changes would be needed to vent a stove in a masonry chimney. Realistically this shouldnt cause any design changes for the builder, but you can guarantee they will try and make you pay for SOMETHING. When we build our home 10 years ago the builder practially wanted money any time I had a question about the construction.

As far as how much the stoves can go down in the "off-season" depends on many factors. If there is a discontinued model, it will go cheaper. On others, it just depends on how motivated the dealer is or maybe there is a stove in a particular color that they want to clear out. Mostly, the off-season is best for scheduling the installation and ordering any parts. That's probably where you will save the most money. Maybe they can even throw in installation for free if they don't discount the stove. There is more bargaining room on everything when they have more time. As far as the motor and boards on the Harman, I only ever replaced one board, but I am convinced the owner of the stove messed it up (there were other issues with this guy). I never replaced a motor or even a blower, even on my own stove. There is fan noise with all pellet stoves and I would always recommend to people that it not be put in the TV room. It seems to bother some people more than others. If you are sensitive to sounds it will bother you. It is kind of like a range hood fan on low all the time.

Any appliance that burns solid fuel - wood or pellets - requires a chimney, although I have recently seen advertisements a "window mount" pellet stove - no mention of code or insurance issues. You will also be faced with clearance issues on both sides. The book cases and furniture are way too close to the potential fireplace opening. Plus a hearth would have to be built out into the room. What you're left with is a direct vent gas fireplace, many of which would fit nicely in the space, assuming it's on an exterior wall. You might be able to cut the required opening as a DIY project, but I'd leave the rest of the installation to the pros from wherever you purchase the gas appliance. There are a number of code and insulation requirements that need to be considered.

Stowy, In most places for $3,800 you could get a nice fireplace insert like an Hampton HI300 and a stainless liner installed, (ballpark). I'm biased to the Pacific Energy brand and would also suggest you look at a PE Summit insert, which might even be less. There are obviously other brands as well. Two things to note: first, virtually all new wood stoves have glass windows, nice for atmosphere and you can monitor the condition of the fire much better. Secondly, stainless flex pipe will not burn out in two years unless you misuse your stove and have a lot of chimney fires in it. It is the mainstay of the industry for most relines. Interestingly, I had almost exactly the same quote for my fireplace. One reason it is so much is that most fireplace flues are 12x12 or bigger. There is much more stainless steel in a 12x12 square liner than a 6" round liner so the cost of the product is much higher. I just bought my own 316Ti stainless 6" liner for $300 and insulated it and installed in about 4 hours with some family helping out. This is going into a wood stove which I put in my fireplace. I thought about an insert but stole a nice used stove at a yard sale for $75 and fixed it up for $50 of parts and paint. I bought $40 of unfaced ceramic blanket insulation, $35 for a stainless mesh wrapper and $5 of foil to tidy up the ends of the insulation. So I'm safely burning in an as good as new stove for just about $500 but as my name suggests I am a New England Yankee skinflint. It is a fairly easy thing to do if you are relatively handy but not everyone likes getting on a roof. A lot of stove shops in my area charge about $1,000-$1,200 for a reline. I would suggest you look at doing a hearth mounted wood stove if you have the room but be mindful of clearances to a mantle if you have one. You'll generally get a bit more heat from a stove than an insert. Also inserts have integrated blowers which need electricity. If the power goes out, it is nice to have a stove which can convect more heat. Good luck