When she arrived, the teenager appeared to be in pain and could only moan, she said: "She wasn't really with it. I think she knew we were there, but she was pretty out of it still.''
After falling an estimated four storeys, Louisa has fractured ribs and a suspected fractured collarbone. She has large bruises across parts of her body where she landed, Ms Kuypers said.
A laceration on her head appeared to be only superficial, and doctors said Louisa had no brain injuries, she said.
"To think she fell all that way and only fractured a few bones.''
Louisa's father Gilbert, two brothers Michael and Chris, and boyfriend Nick Son gathered with Ms Kuypers at the patient's bedside last night. Ms Kuypers and Louisa's boyfriend were going to stay all night, but decided she was just sleeping.
She said her daughter was still too "out of it'' to talk when she left last night, and could only make noises. It was still not clear what happened before the fall, she said.
"Hopefully today we'll find out a bit more.''
Ms Kuypers woke at 5.30 this morning to phone in and check on her daughter after the night. After the good news today, Ms Kuypers is getting ready to pick up Lousia's boyfriend and grandmother, Lois, to spend the day in hospital.
She has been fielding non-stop texts and phone calls from family and friends eager to see how Louisa was, with one friend offering to fly up from Wanganui yesterday.
Ms Kuypers credited her daughter's fitness and strength from outdoor activities as aiding her recovery.
Witnesses were "horrified'' and left shaken after seeing the window cleaner fall while on the job yesterday.
The Department of Labour is investigating.