Ideal House in London stands on the corner of Great Marlborough Street and Argyll Street, just off Regent Street. Ideal House was designed by architects Raymond Hood and Gordon Jeeves for the American National Radiator Company. The design was inspired by the American Radiator Building on Bryant Park in Manhattan, New York designed by Raymond Hood and John Howells and built in 1924. The building was constructed of polished blocks of black granite, ornamented with enamel friezes and cornices in yellows, oranges, greens and gold. The black and gold colours were the colours of the National Radiator Company. The entrances on Great Marlborough Street and Argyll Street were decorated with ornate enamel surrounds, although the surround on Argyll Street was subsequently removed.
The building comprised some seven stories, with a recessed attic storey. The south elevation on Great Marlborough Street consisted of seven bays from the first floor upwards. The windows on the seventh floor are of lesser height than those below. When built, the building extended for four bays northwards along Argyll Street. In 1935 Ideal House was subsequently extended and a further seven bays added. This accounts for the larger gap between the seventh and eighth bay on the Argyll Street elevation (above the entrance).
The building originally comprised a showroom on the ground floor and office above. Today, the building accommodates a restaurant on the ground floor and private accommodation above. The building is now known as Palladium House. The building was awarded Grade-II status on 16 January 1981.