"She knew that at some stage help would come so she just had to keep herself positive by doing things.
"She just kept deep breathing to stop herself from panicking."
After she realised she was stuck Caroline proceeded to push the emergency buzzer in the elevator, however no help came, said Sarah.
There was a light and a fan going in the lift and alarm bells, she said.
"She had a MacGyver moment where she put packing tape in her ears to try and block out the sound."
Sarah said it wasn't until this morning that Caroline heard a car pulling up to the building and began calling for help.
"What she realised was at around 6am people would start coming to use their units so she kept an ear out, periodically shouting from 6am onwards.
"When the ambulance and fire people got there she was pretty distressed because somebody had finally turned up and there was nothing to eat or drink in there."
Caroline's family had alerted emergency services last night when she did not arrive home and got the "ball rolling" with police to try and find her.
"Then the storage unit company rang me first thing in the morning and let me know she had been found in the lift."
Caroline is now at home resting and has been told by ambulance staff to "catch up on rest - just keep going like a normal day".
Sarah said it had been a lesson to the whole family to always take their cellphones with them wherever they go.
Guardian Self Storage general manager Terry King said the company were shocked at the incident which occurred at their branch on the corner of Foundry Rd and Anvil Rd in Silverdale.
"We did get the lift serviced last week and we do have regular services ... so for this to happen, it is as shocking for us as it is for her," he said.
"The lift basically just stopped. We own five facilities and four have got lifts in them and what would usually happen is that there is an alarm system and you push a button if the lift stops ... And it goes through to a security company and the security company come and obviously override the system and get you out.
"In this case for some reason the alarm hasn't gone through to the security company so no one has actually known that [the woman] was in the lift until someone this morning found her."
Sarah said her sister was just happy to have been freed.
"She is very relieved to be out of there that is for sure.
"I think it may be a while before Caroline will go into another elevator."
She said the storage company had told her they would be conducting a full inquiry into the incident.
The sisters have now been given a storage unit on the ground floor so they would not have to use the elevator again.
