I do not recommend staying here. You do not receive the access code for the apartment until 3pm on arrival which can be very stressful for international travellers. There are only flights of spiral stairs to get to the apartments - not mentioned in the listing at all.
No basic instructions for the shower or stove, bed is very uncomfortable, and bathroom is completely different to the photo.
Worst of all was a loud electrical ticking noise that would not stop, coming from a plug socket. Questions to the host about it were ignored. Once in the apartment the host takes hours or days to reply to messages.
While the location is great, so is Oslo's public transport. Stay more comfortably somewhere else.