On December 12, 1902, Andrew, Louise, and five-year-old Margaret Carnegie were moving into their newly completed home, designed by architectural firm Babb, Cook and Willard to fulfill the steel magnate's wish for 'the most modest, plainest, and most roomy house in New York'. What a difference 112 years makes. Now, the former Carnegie mansion has just reopened to the public as the new and improved Cooper Hewitt Smithsonian Design Museum.

Established in 1897 by the collecting granddaughters of industrialist and inventor Peter Cooper as the Cooper Union Museum for the Arts and Decoration, the museum has occupied the landmark Upper East Side mansion since 1976, although then-director Lisa Taylor confessed that the museum had outgrown the place ('a very strong building, not a very beautiful building') before it had even moved in. Plans for renovation and expansion began taking shape in 2004, and a design dream team – stacked with previous winners of the museum's National Design Awards such as Gluckman Mayner Architects, Diller Scofidio + Renfro, Hood Design, Local Projects, and Pentagram – was assembled, along with funding of $91 million.

A decade in the making, the new Cooper Hewitt has gained not only 60% more exhibition space but also the integrated, expansive feel of a true museum, without sacrificing the neo-Georgian domestic charms and exquisite gardens (opening in June 2015) of its unique home. Gone is the impression of an institution forced to tiptoe around grandmother's house with jerry-rigged accommodations to modern building codes.

In its place is an assured fusion of the traditional (a grand wooden staircase, newly revealed Caen stone, the meticulously restored teak room designed by Lockwood de Forest) and the contemporary (a new fourth-floor gallery proportioned to museum dimensions, interactive tables, a smart pen distributed upon arrival that allows visitors to 'collect and create'). 'This renovation allowed us to pause, to take a look at everything that defines Cooper Hewitt, and to ensure that our purpose - to inspire, educate, and empower people through design - informs everything that we do,' says director Caroline Baumann. 'We're aiming to make design fun, illuminating, and immersive.'

That goal is apparent in many of the ten inaugural exhibitions and installations. Among these juxtaposition-heavy shows is an exploration of the changing relationship between designers and users (from Henry Dreyfuss-designed telephones to 3D-printed prosthetic limbs) and the exquisitely presented 'Maira Kalman Selects', in which the author, designer, and artist has created a room-sized collage of objects, including a Bauhaus-era glass teapot, lemon-hued kidskin slippers from the 1830s, and Abraham Lincoln's pocket watch, accompanied by the sound of its ticking-that suggest the sequence of a life, from birth to death. 'The pieces that I chose [from the Cooper Hewitt collection] were based on one thing only – a gasp of delight,' says Kalman. 'Isn't that the only way to curate a life?'