Back in Aug. 2011 a reader shared some scuttlebutt saying Filter Coffeehouse was looking to open a second location in Foggy Bottom. Signage has finally gone up on I St, NW just east of 20th St, NW. Their first store is located in Dupont at 1726 20th St, NW. You can see their coffee menu here.
Below is a peek in the window from their coming soon location in Foggy Bottom. Looks like there will be additional seating upstairs: