He had just arrived home at about 11pm after a night of sober driving and was relaxing with a beer when a plastic smell started leaking through the air conditioner.
When Mr Groube opened the front door, the smoke was so thick he couldn't see in front of himself.
"I'm not sure how I managed to navigate to his porch, I ended up in his rose bush at one stage."
A neighbouring nurse treated the men while they waited an agonising 15 minutes for ambulance crews to arrive.
"It felt like time was standing still," Mr Groube said.
He stayed overnight in hospital for observation.
"I still have a bit of a sore throat and chest."
Mr Groube's stepson Heston Howard has no doubt his father saved Mr Barret's life.
"If Dad got there 30 seconds later he would have died," Mr Howard said.
"In a word, it was terrifying," he said.
Mr Groube dismissed the notion of being a hero and passes the credit to the neighbouring community for their response.
"I just did what anyone would have done, it was instinct, adrenalin just kicked in," he said.
"I think it has brought the community even closer together."
Friends and family of Mr Barret have been coming to Mr Groube's house all week to express thanks.
"There is just so much gratitude."
Mr Groube said that Mr Barret was a good neighbour and friend. The 61-year-old is a night cleaner at Silver Fern Farms Freezing Works.
Mr Barret is heavily sedated and on a respirator with scarred lungs.
A hospital spokesman confirmed he is in a critical condition in the intensive care unit at Hawke's Bay Hospital.
Fire investigators are unsure at this stage what caused the blaze.
