We were a group of 5 friends, and we were unlucky with the weather since it was 40°C in Berlin. The place doesnt have AC, as it is clear in the ad, but there was only one air fan for five people and the house was really really hot in the end of the day when we would comeback from the city.
We opended the windows at night (one of them is broken), but because they are really small and the temperature inside was so high, it almost made no difference.
Also, there are no curtains covering the windows, making it difficult to sleep in the morning.
The kitchen is fine, but doesnt have an exhaust fan, and since the windows are small, cooking made the entire place smell like food and even hotter...
The bathroom was ok, but a shower curtain is missing, so the floor got flooded everytime we took a shower.
The inexistence of wi fi and the stairs were clear in the ad, so we were expecting that.
Overall, the house is well located, but has some problems, specifically if you are visiting Berlin during the summer.