Short answer. Yes and your siding looks to be standard T11 siding or something close to it. You must meet ingress and egress requirements (openings for emergency access). The pro's on this board can give better estimates than me. One thing to consider is in a house that old, you may discover more things that need to be repaired on a project like this. I would find a reputable contractor in your area and get them to give you a general idea on costs.

NO you cannot turn the bottom units into a wall and just replace the top windows as that is what is commonly called a window wall and all on piece top to bottom. Therefore it cannot be partially removed.

Milworkman, I think the question was to replace the entire window unit. From the OP - "Is it possible to turn the bottom windows into wall, and just replace the top windows? " If this is the case, you can remove the unit, frame in a portion of the opening and install new windows in the modified opening. OP did not make any reference to partial removal.

This post was edited by lkbum on Mon, Jul 7, 14 at 16:13

Ok, lkbum I see your point and understand completely. I meant no offense by the capitol NO as my fat finger never left the shift key in time, lol.

I would figure on a full tear out with some cut back on the siding.

Supporting units of that size without a flange is always a bit disconcerting.

We usually fabricate some steel to go between the units and help disperse the load. Seems to work and maintain operation a bit better.

millworkman,
This is the best board on the net. I have directed several friends here. You, WOW and several other pro's provide great info. I've built two homes (literally built them myself) and the last one we had a GC. This board helped me tons with the last house (2 yrs ago) and I still follow this board as a matter of interest. If I had a grumpy cat photo I would post. No offense taken :)