Translation guide
A window system with two panes of glass for insulation and soundproofing.
The standard term for double-glazed windows in homes and buildings.
Literally 'double window'. The most common and general term for double glazing in Japan, often referring to an inner window added to an existing single-pane window.
寒いので二重窓にしました。
It's cold, so I installed double glazing.
このマンションは二重窓で静かです。
This apartment has double glazing and is quiet.
From 'pair glass'. A common commercial term for double glazing, often used by window manufacturers and in home improvement contexts.
Literally 'double glass'. Less common than 二重窓, and may be ambiguous. Sometimes used for double-pane glass but not as standard.
二重ガラスは防音に効果があります。
Double glazing is effective for soundproofing.
二重窓 often refers to a secondary window added inside an existing window, while 複層ガラス refers to a factory-sealed double-pane glass unit. In casual conversation, 二重窓 is widely understood for both.
Literally 'multi-layer glass'. A technical term for insulated glass units (IGUs) with two or more panes sealed together. Common in new construction and window specifications.
複層ガラスは断熱性が高いです。
Double glazing has high insulation performance.
ペアガラスに交換すると結露が減ります。
If you switch to double glazing, condensation will decrease.