A replacement window installed in the existing jamb (frame) is typically installed this way: After cleaning the opening and inspecting it for water leaks, etc. (and correcting such issues), a bead of caulk is applied to the interior of the blind stop. The window is then placed in the opening, sealing the outside edge against the blind stop. The foam or fiberglass insulation (we use foam) is then inserted from inside the window frame. The interior stops are then installed. If there is a gap in the alignment of the stops, a thin caulk line is applied (paintable caulk) to seal that unsightly gap and prepare it for future painting. The exterior is then enclosed with aluminum trim sheet (formed in a brake) and caulked to make it weatherproof. The major mistake some installers make is to measure too close, not allowing room for an insulating product to fit between window jamb and frame. This always causes poor performance and air leaks. We always measure to allow 1/8" gap around the perimeter for insulation product. Michael

But my window looks like the following picture, with the exterior lip as well. Of course the window is so high, that it wont sit like in the picture, and if I stack it higher at the outboard spot, the tilt will be wrong. The interior sill is old chestnut and likely not good for supporting a lot of weight... And on top it is jut a vinyl window that I cant drill into (its a second story install and opening the window is not a not a big deal, so Im not as concerned about the upper security, as I can cut a piece of wood to fit that. But how do I best deal with the mass of the AC on the lower frame of the vinyl window, so it is secured as to not damage the window frame, and ensure that the AC is suitably installed? Thanks very much for your insight and advice!!!

Sounds too cheap to me. Two high quality casement windows alone will probably be $1,000 to 1,200.00 plus other materials and a solid day and a half for two guys and other materials. What brand window is he installing? What type "contractor" is he? Licensed and insured?

@hallettco - Thank you for your help and input. Question for you - you mentioned the new windows are significantly smaller. I'm seeking to better understand exactly what you mean. Whenever you install a new vinyl window, you're going to have a smaller window than what's there, because you're leveraging the vinyl frame/sash instead of just the wood alone. My understanding is that we had full replacement windows, not an Insert Window. Is that correct/accurate based on what you can see in the photos? When discussing the smaller profile glass, I was told that's what happens when you have new vinyl windows installed. Re #4 and the ribbed glass. I actually love the detail and would want to keep it. The problem is that it's single pane and condensation builds significantly on it, then seeps down into the wood. If there's a way to keep that from happening I'm all for it. Can you help advise on how to keep that glass and avoid condensation and wood rot as a result in the future? Thanks again for your help! FYI - the glass we got on our other windows is LowE 3 and is what we would get for these. They're USVinyl Windows (manufacturer is Slocomb Industries) - @millworkman, based on my follow up conversation, we're going with LowE 3, because it wouldn't make a difference and would look different than our current windows.