The wooden bungalow was razed in a Broad Bay paddock on Saturday in a training exercise.
"It's a good opportunity for the guys to put what they do at training into practice," Portobello chief fire officer Bruce Didham said.
"They get a tremendous amount of skill-building. House fires aren't as prevalent as they used to be. I think public knowledge has improved a lot and we're seeing a lot more smoke alarms in houses now.
"A house fire is a pretty uncommon thing these days, which is great from our point of view. When I first started 28 years ago, you could have three or four house fires a year. But we haven't been to a major fire on the peninsula for three or four years now. Six of these guys have never been in a house fire before."
The firefighters initially set fire to a room and practised entry and containment techniques, before allowing the house to burn to the ground.
"We put a pile of old furniture and paper in a room and set fire to it. It fires up really rapidly," Mr Didham said.
"After we set the room alight, we watch the development of the fire as it spreads. It gets lower and lower, which is why we tell people to get down and get out. It very rapidly gets unsurvivable in there.
"A house like that will get up to 500degC, while a modern house, with all the foams and plastics used, can reach 900degC at roof level. The heat generated is really quite amazing," he said.
"By the time we'd finished, there was only the chimney and letterbox left."
The house was more than 150 years old and was believed to be the oldest on the peninsula, owner Alister Young, of Broad Bay, said. He offered it to the fire services.
"I was a bit sad to see it go, really, but it had been getting badly vandalised."
Twenty firefighters from Portobello, Port Chalmers, Waitati and St Kilda took part in the exercise.
