We had a really nice stay at Gerhard's place. It was really warm during our stay, but the room had a nice temperature. We booked this stay during Lollapalooza, a festival in Treptower park. We walked along the lake in like half an hour, so we didn't had to take the warm and crowded bus, or S- or U bahn. Gerhard and his wife (and daughter) we're really nice hosts, very social and inspiring. Thanks for the pleasant stay!