Depends on the depth of the current window, but in most cases the delta is nothing. There were some odd depths back in the day or they could be ordered with different jamb reciever accessories so that math has to be verified onsite with the materials in place. Most times there will be some damage to the returns just getting them freed up from the current windows so unless that is not the case, many applications will require a bit of dress up with a small interior stop to conceal some of the drywall disturbance.

This new construction application will definitely preserve maximum interior jamb depth. Obviously...doesn't come without a cost different too. Is the siding in decent shape or are you looking at a combined project?

The original windows are vinyl double hung. We have expensive blinds and dont want to pull them inward. Contractor said the original windows have a jamb depth of 2 3/4- 2 7/8 inches and the new windows are 3 1/4 depth. That means the new windows will come inward about another 1/2 inch if they install with a nailiing flange window.

Thank You all

Generally speaking, there is a 1/2" offset to the back of the nailing flange. So it sounds like if you set these new windows in a new construction format, everything should be pretty close.

Depending on the window brand you will be using, you should be pretty close. That being said, most times when we do an install with a sheet rock interior return, we usually have to cut back the sheet rock anywhere from 1/4 and 3/8" of an inch. That usually never presents issues with re fitting blinds. Sometimes we get lucking and never have to cut any of the sheet rock which is fairly easy to do.