Dave Ball, 61, of Wellington Road in Broughton, was about to bring his washing in when he could smell smoke in the air.
Mr Ball said: "I came out of the house because I had a line of washing out.
"I could smell smoke and as I walked down the ga
rden I thought somebody was burning something.
At first he thought somebody was burning something in their garden, but when he looked up, he saw smoke bellowing out of the roof of a neighbour's house.
"I looked up at the roof and saw smoke coming out, it was terrible," said Mr Ball.
"Then I went round the front and banged on the door.
"I heard the alarms going off but I couldn't get into the house anywhere."
Meanwhile, Mr Ball had shouted for someone to call a fire engine which arrived within three or four minutes.
He said when crews gained entry to the property the smoke was "unbelievable."
Mr Ball said: "They said I most probably saved his life by spotting the smoke, but anybody would've done the same.
"If I didn't have the washing out, I would never have seen it," he said.
Fire crews arrived within minutes and a 60-year-old man was rescued from the blaze and taken to the Countess of Chester Hospital.
North Wales Police and North Wales Fire and Rescue Service were carrying out investigations at the scene yesterday.
Next door neighbour, George Dougherty, also described the emergency.
He said: "I came home from town and Dave said 'is your house on fire?' but the smoke was coming from next door.
"If it wasn't for his washing, he wouldn't have seen it.
"Dave tried to get in but couldn't and when he looked through the letterbox the house was full of smoke.
"A woman across the road phoned a fire engine."
Two fire engines, an ambulance and the police rushed to the scene after the alarm was raised at 11.50am yesterday.
This morning police confirmed the householder was taken to hospital in a critical condition.
The full article contains 376 words and appears in Evening Leader Flintshire newspaper.
