Mr Turner raced to the front door of their neighbour's house and started banging on it to make sure no one was home while Mr Harper called 111.
Three fire trucks and 12 firefighters arrived to battle the blaze.
The fire started towards the back of the house but really took hold when windows started to blow out, Mr Turner said.
"It started popping windows on that side and we thought, 'Jeepers this is serious'," he said.
"You could hear lots of cracks and glass shattering and lots of stuff in the kitchen breaking - you could hear it.
"Flames were just coming out the window. Just before the fire brigade got here they would have been 2m to 3m high. It was just billowing about 3m wide."
He said the woman who lived in the house arrived home while firefighters were battling the blaze and looked devastated.
A witness, who only wanted to be known as Lianne, was visiting her mother on the same street when she saw the smoke and heard the breaking glass.
"There were flames licking out the windows. It was pretty freaky," she said.
Tauranga senior station officer Kevin Cowper said the house was engulfed in flames when they arrived.
"It was coming out most of the windows on the first floor," he said. "Most of the upper floor has been extensively fire damaged."
He said the couple who lived there were both at work when the fire started.
The fire started in the kitchen, Mr Cowper said.
"What we put it down to was that this morning the power was off in the street and the lady pushed the toaster down. It didn't work but it jammed on.
"She went out and the power came back on and it was jammed on and it overheated."
He said the fire service dealt with many fires caused by toasters kept in cupboards which were jammed on when the cupboard roller door was pulled down.
That was the cause of a house fire on Pitau Rd in Mount Maunganui last week.
No one was home but firefighters saved two dogs in the house.
