姜阿新洋樓建於1946年，費時三年完工，這棟在當時堪稱風華絕代的洋式建築，為姜阿新製茶事業上招待貴賓的場所，同時作為自住宅第，與天水堂、金廣福公館和慈天宮連線，彰顯姜氏家族影響力，形成北埔特殊的人文風景。 

  

姜阿新洋樓的獨特美感，呈現在中西融合的形式風格。半圓拱、凸窗等古典建築技法與裝飾紋樣來自歐洲傳統，從建築外觀即可欣賞多種高難度且精巧的泥作工法，而圍牆的唭哩岸石採自北投，可想見當時的風光榮景；內部大量木構多取材自營林場，烏心石、檜木、樟木、櫸木、香杉等木料交錯運用，細緻的雕刻裝飾帶有濃厚東方吉祥寓意。洋樓設計兼備美觀與實用，例如設置通風口和水斗等巧思俯拾即是，是一令人讚嘆的建築佳作。

 

姜阿新個性浪漫喜好冒險創新，洋樓的起建，乃委託不拘泥傳統的年輕建築師彭玉理規劃，所聘匠司均為在地人，洋樓因此成為北埔鄉親的共同記憶。由於建築工藝特殊，且見證北埔茶業發展歷史，於2001年被指定為縣定古蹟，2018年完成修復，由姜阿新教育基金會統籌營運。

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     Chiang A-Hsin, courtesy name Mao-Xi (1901-1982), is a descendent of Chiang Shiu-Luan, the head of Jinguangfu Land Reclamation Company. In 1932, he constructed a tea production factory (later renamed Yongguang Co., Ltd.), which cooperated with Japan’s Mitsui Norin and Britain’s Jardine Matheson in producing and exporting black tea. As a romantic who enjoyed innovation, Chiang A-Hsin decided to build a western-style mansion to live in and to use as a reception house for his business. He began the construction in 1946, employing architect Peng Yu-Li for its planning. The craftsman who built it were all hired locally, so this western-style house became a special shared memory for the people of Beipu.

     Because of the building’s special architectural features, and because of the part it has played in the development of Beipu’s tea industry, the mansion was designated as a county historic monument in 2001. Its restoration was completed in 2018.