From Berlin Brandenburg Airport (BER) to the apartment: 

(53 minutes) RE8 → S Ostkreuz, change to S41 → S+U Heidelberger Platz, change to U3 → Fehrbelliner Platz, walk 5 minutes to the apartment

(54 minutes) X7 → U Rudow, change to U7 → U Blissestraße, walk 5 minutes to the apartment

(60 minutes) S45 → S Südkreuz, change to S41 → S+U Heidelberger Platz, change to U3 → Fehrbelliner Platz, walk 5 minutes to the apartment

From Berlin Central Station to the apartment:

(22 minutes) RE4 → S+U Jungfernheide, change to U7 → U Fehrbelliner Platz, walk 5 minutes to the apartment

(24 minutes) S3 → S+U Zoologischer Garten, change to U9 → U Berliner Straße, change to U7 → U Blissestraße, walk 5 minutes to the apartment

(25 minutes) S5 → U Wilmersdorfer Straße, change to U7 → U Fehrbelliner Platz, walk 5 minutes to the apartment

From Berlin Central Bus Station (ZOB) to the apartment:

(33 minutes) walk 12 minutes to S Messe Nord/ZOB, S42 → S+U Heidelberger Platz, change to U3 → U Fehrbelliner Platz, walk 5 minutes to the apartment

(40 minutes) walk 12 minutes to S Messe Nord/ZOB, X34 → U Wilmersdorfer Straße, change to U7 → U Fehrbelliner Platz, walk 5 minutes to the apartment