Recently the use of energy-saving glass windows in building design has become very popular. These are used to prevent transmission of infrared radiation into the buildings. Such windows have a thin metal-oxide coating deposited on one side of float glass which attenuates the infrared waves. Although these windows have been quite successful in attenuating IR due to coating, attenuation also occurs for the useful microwave GSM, GPS and other desired signals resulting in poor communication. This paper presents an FSS to improve the transmission of RF/microwave signals through ESG while keeping IR attenuation to an acceptable level. Preliminary theoretical results are presented.