Fire crews found the Tooke Street, Cooks Hill, house well alight about 6am.

The 82-year-old occupant could not be found and several firefighters entered the burning building in search of the man.

Using high-pressure hoses to keep flames away and wearing breathing apparatus, the firefighters searched the house, finding the man lying unconscious in a bedroom.

He was carried through a front window by a firefighter, and taken immediately to John Hunter Hospital, where he was treated for serious airway damage, smoke inhalation and burns.

The Herald understands the man was inside for about seven minutes before fire crews arrived.

Later yesterday morning, he was flown to Prince of Wales Hospital in Sydney for specialist treatment.

The man was last night clinging to life, and was last listed as being in a critical condition.

The firefighters involved in the search of the house were hailed heroes yesterday by NSW Fire Brigade commissioner Greg Mullins.

"The quick-thinking actions of these firefighters played a vital role in this man's rescue," he said.

Four fire crews battled the fire for more than two hours, extinguishing it just after 8am.

The rear section of the single-storey house was destroyed and the rest of the structure damaged by water, heat and smoke.

Police and a fire investigation team from Sydney examined the scene yesterday. It is not yet clear how the fire started.

A room of a Maitland home was also severely damaged yesterday after a fire started just after 9am.

Crews took just over an hour to extinguish the fire, which caused smoke damage to the rest of the house.