We live in Arlington, VA, we are going to spray foam the entire house during the rebuild. We have received a quote from Marvin Integrity casement (all fiberglass). Does any know what is the marvin integrity AI (air infiltration) rating is? I am now thinking of looking at Alpen windows because they have a better rating overall for the same amount price. Alpen 525 series casement has a AI rating of .01. I do like the Inline windows but they have 10-12 weeks lead time. The third quote will be looking at are the Okna Himark series casement just to save money. Any thoughts about Alpen or Okna windows?

Call Marvin, I believe that the Infinity is an A.I of a .11 again this is not the Integrity.

Okna and Alpen are both solid choices can't go wrong with either.

Posted By 4MTM on 03 Apr 2013 12:11 AM
We live in Arlington, VA, we are going to spray foam the entire house during the rebuild. We have received a quote from Marvin Integrity casement (all fiberglass). Does any know what is the marvin integrity AI (air infiltration) rating is? I am now thinking of looking at Alpen windows because they have a better rating overall for the same amount price. Alpen 525 series casement has a AI rating of .01. I do like the Inline windows but they have 10-12 weeks lead time. The third quote will be looking at are the Okna Himark series casement just to save money. Any thoughts about Alpen or Okna windows?

Marvin Integrity All Fiberglass AI = < 0.30cfm (that is the number the manufacturer gives)

Take for instance a high quality window like Intus, in which instance it would show an AI rating of < 0.03cfm

Big difference between 0.30cfm and 0.03cfm


Marvin Integrity Fiberglass - AAMA/WDMA/CSA 101/I.S. 2/A440−08 Performance Ratings

Design Pressure Ratings = 15psf - 50psf
Water Penetration Ratings = 2.86psf - 7.50psf
Air Infiltration (cfm/ft2) = < 0.30
Forced Entry = not shown
Uniform Load Structural Test = 22 - 75 psf


Intus uPVC - AAMA/WDMA/CSA 101/I.S. 2/A440−08 Performance Ratings
*tested on a 3' 03" x 7' 06" Casement/Tilt&Turn*

Design Pressure Ratings = 70psf
Water Penetration Ratings = 15.0psf
Air Infiltration (cfm/ft2) = 0.03
Forced Entry = Grade 10
Uniform Load Structural Test = 105.0 psf


The Intus window was a 3x7 casement/tilt and turn which is a very big operable window. Marvin's used a  fixed window for its test but they did not give a size.

If you are set on fiberglass, stick with Inline, Accurate Dorwin and other Canadian fiberglass window manufacturers.