First, Renewal is average based on performance numbers. Their Ufactor is only a .30 or .29 . Also, they have a rather high air leakage number.
That fibrex material they offer is mostly vinyl and some wood flower( saw dust). That is a fact. They train their salesman to spin the truth about vinyl.

Okna is a very well made/ solid window, especially the 800 " Envirostar". Its also a very sharp looking window.
Their Ufactor is much better than anything renewal has to offer. They have a Ufactor of .26 on their double pane glass,, so its much more energy efficient than renewal. Also, the Okna air leakage rate is MUCH better/ air tight than renewal; its a .01 , which is the lowest in the industry, try asking renewal about their air leakage rate and you will get a song and a dance, they will just say it was tested and passed but NEVER give an actual number. Both Okna and renewal were tested for air, water, and structural integrity by the same rating agency but yet Okna reveals their actual results while renewal does not.
Another fact, the okna has a structural rating of 60 while renewal is 30 or 35 if im not mistaken. Thats almost twice as good as renewal.
Okna does also offer a composite called Starmark which is also very solid.
That said, there are very poor quality vinyl windows. Believe it or not, Andersen offers one of the lowest quality windows in the industry called Silverline and so does Pella in my opinion. Stick with high quality vinyl offerings if you want maximum energy{{gwi:9241}} efficiency, long term durability, and looks. Stay away from MI , alside, and the other low end stuff.

This post was edited by mmarse1 on Fri, May 9, 14 at 8:33