I would definitely invest in a better window. Excalibur has a very high air infiltration rate compared to windows from Okna. Gorell, Simonton and Softlite.

+1

Better to spend a bit more money once than cheap out and get a bad window for cheap that will need to be replaced again.

I agree. the excalibur is a low quality winodw. in fact, i am not a fan of any alside window. Alside just are'nt good at making windows,particularly the excalibur. most contractors who know nothing about windows bring the excalibur,silverline,pella vinyl windows,or Xact because they are so cheap and they can sell it to customers who only care about price and not quality. however,after a few years the home owners need to buy new windows again and suddenly those cheap winodws become super expensive when they need to replace them again because the winodws leak air and fail.
Okna make one heck of a window as does gorell and vanguard by sunrise.