Composition - Great use of some major aspects of photography. First glance shows me some nice use of negative space and leading lines. THe contrast between the blue sky and the dark room is effective. The white mortar stuff around the window is a little distracting, but its overall effects are pretty mild. The contrast is the great thing. I see you other commenters also noticed.
Technique - Excellent exposure on this one. The framing looks like it would be a little better if the window (and this is my eye seeing this, maybe not everyone's) didn't appear to be tilting toward me at the bottom. It might've been better to square up the window with the picture even if it isn't really like that. It would look better I think. DOF is good and the picture is pretty sharp.
Overall - This is a pretty good pic. It could use a little something in the composition to show either some despair on the inside or something a little happier on the outside. I keep thinking in my head of a hot air balloon out the window or something like that. I think the despair angle would be a better one to pursue. Its a nice image and definitely has its place. Nice photo and good luck in the future - Inspzil