In a manner reminiscent of the Muggle Prime Minister, Einar had use of a set of spacious rooms "over the shop". In his particular case, this puts them on the Eighth Floor, close to the Atrium. Einar's more feral and territorial instincts, the relicts of years on the street, tend to come out here, and Ministerial staff are generally advised by colleagues who care for their health to give the place a wide berth - except in demonstrable emergency circumstances.
As the few who have crossed the threshold can attest, this place is minimally furnished - functional, but not anywhere near the mainstream concept of comfortable. About the only bit of real colour in the place is the fresh flowers Einar had placed, every day, in his kitchen - a tradition not yet discontinued. The one well-upholstered area is the library, although this seems to be for the succour of the various volumes, rather than any potential reader, as the repository has the same semi-abandoned air as the rest of the rooms.
As a perennial 'relocator', Einar showed little inclination to truly treat the place as home, in the sense most people would understand that term. He did, however, "retire" here often, even sometimes in the middle of the day, so for him at least it clearly offered some kind of refuge from the world.
With Einar's passing, the flat has reverted to the Ministry, and is currently occupied by Karith Black (still) and Draco Rookwood, whose own property is known to have been compromised on security grounds.