The rescue service has had a large operation on site during the night.
The fire started on a balcony and then spread to two apartments at the top of the house and further up onto the attic, said Marie Nordahl, operations leader at the rescue service earlier.
At least five apartments have been damaged and a total of around 40 residents of the three-story building have been evacuated, according to Uppsala Nya Tidning.
The firefighting efforts were hindered by the solar panels on the roof.
They sort of contain the fire, says rescue leader Marcus Nordalen to the newspaper.
There is no information about personal injuries or any suspicion of crime.
