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/(m(2)K) to less than 2.8 W/(m(2)K). The water condensation resistance is enhanced. The visual transmittance and haze are satisfactory. The structural resilience of the hollow structure is excellent. (C) 2019 Elsevier B.V. All rights reserved.