The fires have been raging since Monday night.
Frost and his partner Wade initially sat and watched the fires in their as-yet uninsured rented home.
But when a chopper crashed on Tuesday afternoon, claiming the life of war hero and pilot Steve Askin, Frost knew he had to get home insurance.
Yesterday morning, he got it signed off.
Hours later, his home was gone - or so he was told.
Frost left work at 11am yesterday, with a bad feeling.
As he went up his hill, he stopped to talk to a police officer "who said there was no risk" to his home.
But shortly after midday, the wind shifted to the northeast. It changed the direction of the fire, which soon began raging down the valley.
Fires rage in the Port Hills last night. Photo / Oliver Watson Frost said it quickly became apparent that they needed to leave.
By 2.15pm, he evacuated with only his dog and cat, along with his passport "and the clothes on my back".
He went to the bottom of his hill and watched the flames "get closer and closer to our houses".
At around 6pm, he went to a friend's house. Later that night, he saw footage of his house, which showed it still intact.
Shortly before midnight, he ventured for a closer look.
"From what we could see, our house was actually glowing," Frost told the Herald .
"It was just by chance we spoke to a gentleman whose partner was in the police and she was able to say, 'yeah, that house is gone'.
Helicopters are hard at work bushfires in the Port Hills above Christchurch. Photo / Alan Gibson. "We just sat and watched the hills burn for a while, for a bit of closure."
Frost still feels "numb" but feels "so lucky" that he got insured yesterday.
"I woke up [yesterday] morning and thought, 'I've got to do that now', so I did it. We're really lucky."
But later yesterday, a Fire Service contact told them that their house might've survived.
The Herald was then able to show them images of Worsleys Spur taken from an NZME reporter at around 4pm today which showed their home intact.
Helicopters are hard at work bushfires in the Port Hills above Christchurch. Photo / Alan Gibson. "It looks like a lot of our property is burnt, but we're all good. We're pretty lucky, which is really really good news," Frost said tonight.
Frost had been offered places to stay by friends and a local house builder.
But now, he can return to his home as soon as the cordons are lifted, which is not likely until Saturday.
"We talked to our neighbours next door and you can see their house gone and they are gutted," Frost said.
"Our hearts go out to them and we'll do what we can to help them out once we can get back in."