1.
double window; double-glazed window
A window with two layers of glass — either a single frame containing two panes (double glazing) or two separate window frames installed one in front of the other — used to improve insulation against heat, cold, and noise. Common in cold regions and increasingly installed in ordinary homes for energy efficiency and soundproofing.
二重窓の部屋。
A room with double windows.
二重窓にしてから部屋が暖かくなった。
After installing a double window, the room has become warm.
線路に近いアパートだったので、二重窓にして騒音を軽減することにした。
Since the apartment was close to the train tracks, we decided to install double windows to reduce the noise.
Composed of 二重 (double, two-layered) and 窓 (window). In Japanese, 二重窓 covers both what English-speakers call "double-glazed windows" (one sash with two panes) and what are called "storm windows" or "secondary windows" (a second window frame added inside an existing one). Home renovation ads often use it for the latter type.
CULTURAL NOTE:
Traditionally associated with cold regions such as Hokkaido and Tohoku, where 二重窓 are essential for winter insulation. In recent years they have spread across Japan as a retrofit for soundproofing (especially near busy roads or rail lines) and for reducing heating/cooling costs.
COMMON COLLOCATIONS:
- 二重窓にする: to install a double window
- 二重窓工事: double-window installation work
- 二重窓の効果: the effect of a double window
- 断熱二重窓: insulated double windows
SIMILAR WORDS:
- 複層ガラス: multi-layer glass — the technical term for double-/triple-glazed glass
- 内窓: inner window — a second window added inside an existing frame
- サッシ: window sash / frame
- 断熱: heat insulation — the goal of installing 二重窓