I am having windows in my 1950s era home replaced.

I started getting quotes last year but gave up when the quotes came is so off � one company quoting 1,000 per window, but the others between 5200 and $5900 for 16 windows.. This year I have gotten two quotes, they are about $2000 different, so between 5300 and 7500. Any advice?.

quote 1.
Okna Custom Made INSUL-TEC(500 series) Deluxe Double Hung Replacement Windows,
Welded Sashes and Frame,
Non-Recycled(Virgin Vinyl)
Insulated Sashes & Frames
Interlock System at Meeting Rail
Triple Seal Around Sashes
Double pane high energy efficient glass with Low E/Argon Gas
Double Locks On All Units Over 24" Width
Window Test Results
DP Rating R 50
U Factor .25 With Grids-.20
Air Infiltration .02
Solar Heat Gain .26
Optional grids
Measure and custom bend vinyl coated aluminum trim for exterior sills, sides, and header for each new window
Install and seal exterior trim

Quote 2

Signature Series silver plus Double hung
Foam Wrap around frame
Argon gas and low e coating
Customer exterior trim
Add or remove mull
Glass breakage warranty, argon gas fill, low e coating, foam wrap
u-factor .28
Solar heat gain coefficient .30