"Immersion Room", an interactive space that provides visitors digital access to the museums collection of wallpaper. The main exhibition space was expanded and the museum had a custom open-source font, which remains available for free download and modification, designed for its reopening. In 2015, the terrace and garden renovations were completed and opened to the public, with design led by Walter Hood. In 2016 the museum introduced the use of digital pens for visitors. Museum building The Cooper Hewitt is located in the Andrew Carnegie Mansion. The Georgian style mansion was built over the course of the years 1899 to 1902 and has 64 rooms. The home served as not only the home for Andrew Carnegie, his wife, and daughter, but also as his office for his philanthropic work after his retirement. The mansion was designed by Babb, Cook & Willard. It was the first private residence in the United States to have a structural steel frame. It was the first home in New York to have an Otis elevator. The elevator is now in the collection of the National Museum of American History. The home also had central heating and an early form of air-conditioning. The property has a large private garden. In 1974 it was added to the National Register of Historic Places. The conservatory, which is made of Tiffany glass, was renovated in 1975. In 1995, the museum closed for a year for a $20 million renovation to connect the three buildings on the property, improve accessibility, and build a design study center. Funds for the 1995 renovation project included $13 million from the Smithsonian Institution and a $2 million donation by Agnes Bourne, an interior designer. In 2008, the museum started to undergo renovations. The renovation cost $91 million and was the largest in the museum's history, partially financed by the museum endowment. The museum reopened on December 12, 2014. Additional renovations were completed in 2015, including the property gardens. To celebrate the reopening of the museum, the Cooper Hewitt released a downloadable 3D scan of the building, allowing users to explore the mansion from their computer, reuse and remix it, and print a 3D printer version of the building. It was released under a Creative Commons Zero license. Collections The Cooper Hewitt collections consist of decorative and design objects. The museum's original collection focused on architecture, sculpture, painted architecture, decorative arts, woodwork, metalwork, pottery, costume,