Experimental analysis of seasonal temperature characteristics and cooling and heating energy consumption of a slim double-skin window

•We develop a slim double-skin window with a 20-mm-thick air cavity and single frame.•Heating and cooling energy use was analyzed through a 15-month testbed experiment.•The proposed window exhibits comparable energy efficiency to double-skin façades.•The life-cycle costs are 47% lower than those of double-skin façades. We developed a slim double-skin window (SDSW) with the aim of reducing building energy consumption for cooling and heating, thereby reducing the impact of buildings on climate change. The developed SDSW is a slim structure with an air cavity thickness of 20 mm, i.e., thinner than that of a traditional double-skin façade (DSF). We analyzed changes in the thermal properties and cooling and heating energy consumption of the SDSW as well as the effects of the thin air cavity on window performance. A testbed was constructed to analyze the seasonal temperature properties of the glass and the cooling and heating energy consumption. We also compared the long-term effects of the air cavity on the difference between outdoor and indoor glass surface temperatures under similar conditions for the SDSW and traditional DSF. The SDSW temperature was 3 °C lower than that of the traditional DSF, and the cooling and heating energy consumption dropped by 6.5%. Although the performance of the developed SDSW was comparable to that of traditional DSF, the life-cycle cost was reduced by 47%.