I have Thermal-Gard vinyl replacement windows in my home. They were installed a couple of years before I purchased in 1996, so I can't provide an original cost. They have held-up fairly well. After 20+ years, several of the triple glazed panes have lost seal integrity and are experiencing condensation and mineral deposits between the panes, though this is not unusual for windows of this age. The frames and sashes are in good shape with no discernable sagging. There is some damage to the locks and stops. I have been looking to replace the windows due to the amount of fogging due to seal leakage. I hope to be able to replace the sashes + glass with parts from Thermal-Gard to avoid having to remove the frames, but it seems that there are few distributors still in business and the manufacturers website and facebook pages are not providing much info. The copyright year on the webpage is 2015, so I presume that if they have gone out of business, it has been very recently. Vince