•Proposed an alternative low-e film installation approach—elevating it from window-pane to reduce thermal transmittance of window.•Experimentally and theoretically studied the thermal insulating performance of the elevated low-e assembly.•The optical and mechanical properties of this assembly were proved to be desirable. To minimize the heat loss through single-pane windows, we investigate the effects of elevating low-emissivity (low-e) film from glass pane. With an insulating air gap, not only heat conduction but also radiative thermal transfer can be suppressed. The thermal transmittance is reduced from 5~7 W/(m2K) to less than 2.8 W/(m2K). The water condensation resistance is enhanced. The visual transmittance and haze are satisfactory. The structural resilience of the hollow structure is excellent.