Utterly confused about installing Marvin Ultimate Insert Window
I'm back with more questions about the Marvin windows we got (wish I'd just gotten the Loewen I'd really wanted, at this point in time).
We are needing to replace one window that has failed and is currently stuck open - while the north-east goes through -10degree days, thanks very much!
Well, we ordered a "Marvin Ultimate Insert" aluminium clad replacement window as it sounded from long analysis like it would be the way to go for a replacement in an old house without disturbing old horse-hair plaster walls or without disturbing the exterior too much which is all in great shape, actually. There is no indication of any rot, the window opening looks sound. There is a storm window outside also.
Having received it, I've been looking it over to understand the installation and I am completely and utterly baffled. This thing seems like it is designed to slip into the window opening without ever having to directly touch too much of the house. Is this correct?
I was utterly surprised to see no nailing fins for one thing.
Having spent an age reading about the necessity for proper window and door installations to ensure good insulation from air infiltration and - perhaps even more important - to ensure a good seal against water penetration, I don't see how, if they followed the Marvin instruction, the installers would effect the house wrap when the old window comes off, or how we'd make a decent seal against water penetration without the nailing fins. Marvin's instructions seem to suggest - if I understand it correctly - that a 1/2" thick bead of caulk (sealant), directly exposed to the weather (NE: -10deg temps, snow, sun, rain etc.) would be all we'd have between the house's window-opening framing members, and the replacement window's frame itself.
Can anyone explain to me if
(a) if I've understood the "Ultimate Insert " instructions correctly,
(b) this is a halfway decent window concept at all and lastly, and
(c) assuming that this "Ultimate Insert" stuff is alright, is there a sure way of installing this that will ensure that in 5 or 10 (and ideally more) years we don't have a case of house-rot on account of a dodgy window and/or installation? We don't have any rot or any such thing of the window. But then, we do have exterior storms that we were thinking (hoping) to remove and that would certainly expose the frames to more moisture.
Extremely nervous home-owner.