Nana is a perfect hostess and her house is perfect for up to 4 people.
We were with 5, but we found it no problem to use the bank for sleeping. The house is really beautiful, modern and clean. With all things we were enjoying with: dishwasher, coffee machine, milk foam machine, wasmachine, dryer, douche, bath. All was clean, and the linnen and towels too.
When I had a question for Nana, I could Whatsapp her, and her responses were always quickly. She remains kind and friendly.
I highly recommend her and her house as a base for discovering Berlin.