I took the plunge, and bought my first window "pocket replacement" as part of my daily Lowe's spend. But before you put a window in, first you gotta take one out. Total time: about 20 minutes. So easy, a child could do it! It was made somewhat less stressful by my selection of a window that has no glass remaining in it, but it would have gone just as easily with a more breakable window.
Here is our first victim in its native environment. Crikey, he's a big one, and he's not happy to see me!
Here's the structure of this window. On the far inside, there is a strip of wood about a quarter inch thick and maybe two wide. It holds the lower sash in place. (A "sash" is the part of the window that moves. There are two of them, even if one can't move.) So first, we free the lower sash by removing those strips. There is one on each side, and one on top; the ones on the sides come out first.
These are our tools. The pry bar thing is a molding remover. The hammer is a hammer.
After the side strip is removed, see how the sash is just hanging there? Now do the same on the other side. Be careful to hold the sash in place as you finish the other side, then carefully lift the sash out. Assuming your sash still has glass in it, anyway. Mine didn't.
Here's the molding remover in action on the top strip. None of this required any exertion at all, by the way. It all comes out easily, even after ninety years and God knows how many coats of paint.
The top sash is held in place, and separated from the bottom sash, by a square strip maybe half an inch on a side. So next we remove that.
Except -- oops -- the sash actually holds it in place. Since nothing yet had required any exertion or destructive force at all, I considered the situation carefully. Clearly things weren't meant to be done in this order...
After it's removed, this pin still holds the top sash in place. This is what the pin looks like after I pulled it out with a pair of pliers (not shown) -- it's spring loaded and moves easily, after ninety years. Unless these windows were replaced sometime after the construction of the carriage house in 1920, that is. But they look original.
When the top sash is removed, there's one more strip of wood. Don't take that out. It's the blind stop, and it holds the replacement window it. You can't take it out anyway, because it's not just a strip on the frame, it's integral to the frame. Yes, I found this out the hard way, but the bit I split off was easy to nail back in place, and after I discovered its integrality, I checked the instructions for installing the new window. When all else fails, read the instructions. At any rate, the blind stop is important, so leave it.
And so we're done, and it was all so easy the aloe vera didn't need to be moved. My only disappointment is that the storm window can't be removed from inside; I'll have to get on the ladder to get it off. But that's all right, because it all needs paint out there anyway.