I work for Barrier Windows so it may be easier for me to clear up some information about our windows and competitors.
Competitors make window frames out of vinyl. Vinyl is composed of all sorts of recycled plastics that have been treated with acid baths and bleached numerous times (6 to be exact) and after are melted down and bleached again to make vinyl window frames. These frames are weak, they warp, and stain very easily. They are weak because of the amount of processing, they warp because of the amount of times they have been processed and because they have no reinforcement inside of the frame (vinyl has low structural integrity), and they stain because vinyl is porous meaning when it is warm the pores in vinyl open up and is susseptable to getting stained.
Vinyl windows have a double paned glass, separated with an aluminum spacer, and filled with argon gas. Regardless in direct sunlight or not, the temperature changes in the vinyl window will allow that aluminum spacer to expand and contract very slightly. Unfortunately when that spacer contracts even a little bit the argon gas inside will leak out. This will occur early in the life of the windows, leaving your window inefficient within a year or so. Vinyl windows will save you at best 10% off your fuel bill at a depreciated rate. Of course this isn't ALL cases but it is a lot of cases. The reason the insides of your windows also get cold in winter is because the glass on the outside gets cold, transfers to the spacer, then transfers to the inside pane.
Barrier windows have NO aluminum to aluminum contact, i don't know what the sales rep may have showed you, but the two spacers in between are steel and are separated by a Poly Thermal barrier that prevents any sort of conduction from glass to spacers and spacers to inside pane. Our frames are made out of PVC which is PURE un-recycled vinyl. This vinyl is also reinforced by aluminum inside the frame so it never sags. PVC doesn't stain, or warp.
Barrier guarantee's you a double lifetime warranty as well as a 40% energy pledge. The quality in these windows you cannot beat. You may have dealt with a newer associate and if that is so i would be more than happy to come out and go into great detail about windows as i have been with the company for some time.
A home is normally a persons largest investment and i like to see them put in a product that they get what they pay for. If you have any questions you can reach me at 970-571-3434. My name is Chris Conacher and i would be happy to answer and and all questions that you may have. I hope the information i gave you will help you with your decision, i work for my company even off the clock