We stayed at the basement place which is mainly a budget thing, and the experience is probably way different in one of the up upper rooms. Shaun is mentioning the noise from walking upstairs, which I was prepared for, however the constant buzzing from the air condition room was quite loud. Later we learned that there was some kind of malfunction, also the host himself is staying in the room, so I guess we were just unlucky. The house is clean and cozy, Shaun has prepared an efficient and comfortable way how to accommodate us even while he was at work.
I don't understand comments about the neighborhood. Yes it's populated by black people. So? All the people we've met there on the way to and from the metro station have greeted us with a smile. Also it's well lit in the night and quiet.
Next time in D.C., I'd gladly stay at Shaun's again, but this time in the upper room.