Energy-Saving Glass (ESG) is used to prevent the penetration of infrared (IR) radiation into buildings and hence to maintain thermal comfort. ESG is made of float glass with metallic-oxide coating over it. Unfortunately RF/microwave signals are attenuated by this coating making communication more difficult. Multi-layer float glass windows provide another solution that can offer thermal comfort inside buildings. This paper presents a parametric study on the transmission of RF/microwave signals through float glass panels. Single, double and tripple glass panels are analyzed and the effects of the dielectric constant, thickness and gap between panels are considered. It is observed that with appropriate selection of parameters high-transmission band can be changed to obtain best transmission at some frequencies while stronger transmission at the lower frequencies (e,g up to 2GHz) or wider passband with larger passband ripples can be obtained.