What are the rest of the windows that are currently in the home constructed like?

Are they wood windows...? If so, a pocket replacement will do just fine and probably give you the most straightforward and solid install.

Depending on the window that you have and application associated with it, that will dictate how you should proceed.

The rest of the windows are wood, but I plan to replace them all eventually.
I'm remodeling the room where the windows will go, so I don't need a replacement window. We are down to the studs. I need either new construction or replacement window with fins. I just don't know if there is a difference.

If you are down to the studs with all the interior trim removed, your options are going to be full tear out or full tear out with nailing flange.

If you are not disturbing the exterior trim or you have a non-removable exterior detail around the window (i.e. brick, fiber cement, etc), you are going to be relegated to full tear out without nailing flange.

There isn't any real difference between a pocket window and a full tear out window (i.e. in the window) at that point if you don't use the flange. Its all application at that point.

yes we are going to redo the exterior trim. So the window is full tear out with nailing flange? Haven't heard that before. Is that compatible with the okna 400 and 500?

Okna 500...yes.

You will need to order it with the fin.

+1. You want the 500 series with integral fin, also know as the 5500.
Also for reference, in vinyl, replacement window with fin and new construction window = the same thing. They are all 3 1/4" jamb depth, and exactly the same with only the addition of the fin.

does Okna 400 come in new construction option (with nail fin?)

From what I know all of the Okna window series are available with a fin for new construction.

I stand corrected, thanks WoW.

I am going to guess that you are sitting in this case.

Don't hold me to that either as we never order the 400 at this point. The lack of an accessory groove makes that window mostly worthless to us.

No nail fin, no accessory groove, and only marginally less costly than the 500. 500 is the better option 99% of the time.

First, thank everyone for the speedy responses, your insight is very helpful. Seems like Okna 500 is definitely the preferred option. I have a follow up question. I am in between Okna 500 vs. Interstate 8800. Interstate is definitely smaller and less known. Can anyone comment the difference between them is substantial? The price differential is ~$50 per window with Okna being more expensive. Thank you!

They are both fine windows having used both. I am a bit more partial to one, but both solid performers. How do the two installation companies stack up in a comparison?

Installers are great and basically identical, so I can't use that as a differentiating factor. The outside profile of Okna 500 is a tad nicer, but the combo tilt/lock mechanism of the Interstate is nicer. Total price differential is $250 (only 6 windows) with Interstate 8800 being cheaper. While nice, it is not a huge deciding factor. If I may ask, which one would you put in your house?

I have neither in my home (newer construction), but I did put Oknas in my father's home.