I purchased 6 Fibertec windows in 2008, as recommended by my architect. Fifteen years later I am sorry I did so. A few weeks ago the lower sash fell out of the unit and smashed. No one was in the room and the window was not open. This was obviously very upsetting. The person I spoke with in customer service immediately said "that's impossible", basically saying I was not describing what happened accurately. I forwarded the warranty and that same customer service person pointed out that "broken glass" is not covered. I can understand if a baseball hits the window, but this was a catastrophic failure of the unit. So I thought, OK, terrible but I at least I got 15 years out of the window. I'll I need is a lower sash replacement. I asked what would that cost? Surely that would be far less than a entire new unit. No response at all. The fact that this company is uninterested in what is clearly a defect speak volumes. They should have sent someone to inspect the window and find out why this serious event occurred. The window is very heavy. If someone had been sitting in the chair near the window they would have been in the hospital. So, the customer service person was not responsive, abrasive and not interested in what had happened. His whole purpose was to put me off. Which he did. A new Pella window will be installed in a few weeks. I would never recommend this company to anyone, based on my experience with their product, their warranty and their service.