We purchased Comfortworld 6000 replacement windows from Window World two years ago for our 56-year-old home with its original windows. I can't say enough about the professionalism of this company and the quality of its products. An easy-to-read menu allows you to customize windows your way. You can choose from basic, vinyl replacement windows to double pane, gas-filled premier windows with interior grids. They tilt in for easy cleaning and contain screens that pop in and out for storage or cleaning. We added custom exterior trim and were able to get high-quality windows at a fraction of the price of the home store, department store or other window companies. Our Window World representatives were not high-pressure salesmen like some of the others we encountered and they stand behind their products, which come with a lifetime warranty, including glass breakage. When we had an issue with a large bay window, the company owner himself came out and made the adjustment. The windows are beautiful, soundproof and add value to our home.