An appropriate window-to-wall ratio (WWR, the proportion of the total wall area occupied by windows) for most buildings is 30 %. Another percentage point of window area increases electricity consumption by 1 %, but some architects in their quest for stylish aesthetics, may design floor-to-ceiling windows that account for 100 % of the building's wall area.
一般大樓適當的開窗率（窗戶面積占所有牆壁面積的比例）是 30 %，窗子多開 1 % 就多耗電 1 %，但有些建築為追求時尚美感，竟然設計多達 100 % 的落地窗。