"Wow!" you say, as you come to the realization that you have a lot of choices as to the style, brands and materials that you select for your replacement window project.  As we covered in our article on The Cost of Replacement Windows and Patio Doors  there are distinct differences in the cost of replacement windows and patio doors available to you. But, the cost is just one of the important considerations you should have.  Another is the energy efficiency and comfort performance of the windows and patio doors. We at Jantek  want you to understand why that is, and so here we go!