Because the energy saving windows have special coatings/films it can interfere with your cellular reception. Some cellular providers (Verizon and At&t) have specialized devices that enable you to use a wifi connection inside your home that works similar to a receiver/amplifier. The device is typically referred to as a MiFi (but is marketed differently by each company). Hope that helps.
I have instally thousands of dollars of energy saving windows, my entire house. Now I can't use cell phones inside my home. IS that issue related to the windows?