Expensive is a relate concept. It is going to cost in the mid to high thousands.

Do you need a FP for heating? If you really want help we need to see a to scale floor plan with all measurements clearly marked and what is outside the wall . Aslo do you have TV in the space ?

we would definitely use the fireplace to heat-because it has high ceilings-all the other rooms we are not sitting in are getting warm and this area is still a bit chilly i want to replace the slider and put the fireplace there-in the exsisting hole -a patio is on the other side - i would like the television over the fireplace

25-50K for the whole completed concept would be the starting on basic pricing. It depends on the specs. You need to design, diagram, and specify exactly what you want to start with. Or pay a designer to do that for you if you don’t know how. There is no top end if you want Pinstagram images like bookmatched slab stone chimney breast and folding stacking doors like Lacantina.

There is likely a better location for the fireplace and you'll save $$$$ if you select an electric fireplace over one with gas.

Also have you thought about the appearance of the fireplace from your patio? It's not an attractive appearance.

I added a gas fireplace where there once was a wall. Total cost with finishing, around 9K. It was built into the room, which you can do but then you'll have to finish out the rest of the wall with shelves or something so it doesn't look stuck on the wall. Also, I could take advantage of some existing venting that was already cut through the roof and abandoned when I got a high efficiency furnace that vented differently. So lots of advantages that made it less pricey. Replacing a window with a door is at least 2K, depending on the kind of door, maybe more. Here's a picture of the fireplace, not quite finished but close. Originally this was a blank wall. Love it but it wasn't cheap.

It looks amazing!! i want to do something like this -simple with shiplap

Shiplap is a trend that is over unless your home is a Joanna Gaines farmhouse. The room looks to be quite dark and you're wanting to eliminate your biggest source of natural light. What other sources of natural light are in this room? What do you plan for ambiant, task and accent lights?

IMO to plan to hang the TV over the FP is bad planning that is IMO the worst place for a TV . Maybe post pics of the whole space and I agree an electric FP can give you heat and be so afforadble and go where ever you want it . I do not see giving up a really nice glass area for light to replace with a big heavy FP and no real light in that space . I agree that ship lap which BTW is not actully shiplap has been a dated look for a long time already .

I know ”shiplap” is trendy and may be dying out -but we live on the coast and wanted a “beachy” look -having a contractor over to price it out i am planning on putting two small windows on either side of the fireplace-if i end up doing it —as far as the television-totally agree about the vision height-i dont plan on having much of a hearth so it should be good ill keep you posyed!