Installing a Tight Fitting Wood Insert

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Sampson100

New Member
Oct 1, 2025
2
Milwaukee, WI
Hello!
I've been getting quotes on wood burning inserts. My house has a fireplace that needs a lot of expensive work to the firebox and chimney flue. Instead of putting money towards those repairs, I have decided to go the insert route.

The model I'm considering is either the Lopi Medium or Large Flush Wood NexGen-Hybrid. My fireplace opening does meet the required minimum measurements for the large flush insert, however it is pretty close. One of the companies said they could do the large insert, while the other company said they wouldn't do it because the fit would be too tight and it would be difficult to hook up the liner to the insert with such little room to work with.

My questions are:
1.) Is it possible to hook up the liner (correctly and safely) to the large insert with very little room to do so? Why would one company be willing to do so and they other not? The company that said there wasn't enough room to do the install suggested the medium size insert.

2.) If I can fit the large and the company is willing to do so, should I go for it? The main reason I prefer the large insert is that I want the biggest viewing window possible. The viewing window for the medium is 40% smaller than the large insert.

3.) The fireplace is on the first floor in the living room which is open to the dinning room and then a doorway to the kitchen. The first floor is probably 1,200 sq ft. At the other end of the living room is a semi-open staircase that leads to the 2nd floor bedrooms (probably another 800 sq feet. With the large insert, would it be possible to heat the main floor and the second floor? Or would it be difficult because of the stair case? If its implausible to heat both floors, I'm wondering if the large would be overkill for the ~1,200 sq foot main level.

Anyways, thanks for taking the time to read all this! Any information/opinions are welcomed!
 
The best thing to do is to ask the company for more details on the installation of the large insert. The liner can be attached from the inside of the stove with the proper adapter. That would be my guess about their method. If they are using this method, as long as they have measured carefully and the top back of the insert doesn't hit the rear slope of the fireplace, then it should be ok.

[Hearth.com] Installing a Tight Fitting Wood Insert

Sizing for heat depends on several factors, like how open the fireplace room is to the rest of the floorplan, amount of windows, quality of insulation and sealing, etc. It will probably we ok. One can burn smaller fires, just 2-3 logs at a time, for less heat.
 
Thanks for you're reply! Is that adapter to attach from the inside specific to Lopi, or is it universal for other inserts?

Also, is there any reason to be concerned with that type of installation -- connecting to the liner from the inside of the insert? Any safety or performance issues?