How much more per floor?

I can answer your question through an appraiser's point of view. Firstly, It would depend at the purchase prices homes bought in price ranges of 100K-300K it would be a difference of $500.00 per floor location. Homes worth 300K-600K floor location would be valued at $1,000-$1,500. 600K-1MM it would go from $2,000-$2,500, and homes above 1MM is on a case by case basis. However, I have sometimes given value for floor location above $20,000. It can still be further adjusted for views, however 2 floors usually don't make such a major difference.

http://www.millersamuel.com/repost-measuring-manhattan-values-by-floor-level/

careful how the market will value renovation differences...but what I would advise is that back in the day, new devs gave aprox $25K per floor as a premium for better views. I would say the norm right now for existing resale is somewhere between $15K and $20K per floor.

http://www.urbandigs.com/2011/11/floor_multiplier_valuing_low_f.html

Now, there are two things to keep in mind:

1. Is there a drastic difference in view? Think of Unit 35A compared to unit 30A. Chances r both have great unobstructed open city views so 100k diff might be too much. If there is not a drastic diff in view you should lower the multiplier. If there is a drastic diff, say 7A sees park views but 4A doesnt, then you need to raise that multiplier!

2. Is there a small or large gap in floors? There is a diminishing return the larger the gap is. For example, lets say we assume 20K per floor and be safe. Now we compare unit 25A to unit 5A. Is 400K really the diff the market will be able to absorb? Prob not. If there is large gap, you need to lower that multiplier as well.

The combination of these two forces is the art part of doing this correctly to try to accurately value how a buyer may value views.

See http://streeteasy.com/talk/discussion/29523-price-differential-per-floor