Window4U (IL) wrote:
Of the three I would give the nod to the Okna 400. Okna has a better air infiltration rating and a better spacer with the Okna using Duralite composite spacer and the other two using a U-shaped metal spacer called Intercept. Okna's Duralite has warmer edge of glass ratings which will help reduce the chance of condensation.
I would ask the Okna salesman to make sure he included the "Deluxe" package which includes another layer of Low-E coating, a locking screen and foam filling.
In my opinion you would have a real nice result using the Okna 400.
This is a great explanation here. The 400 series is Okna's "entry" level line but it is hardly entry level.
Ask for the Deluxe upgrade and you will have a far superior window to the other two offerings. Lower Air infiltration, better thermal numbers, more glass, etc.
Once you are comparing premium products, installation is the critical separator at that point so make sure you company is up to date on the latest methods and materials.
There is a poster on the board that serves the NY area by the name of "buddy" and he is a very good contractor to deal with and is absolutely on the cutting edge.