They said Tuesday's blaze was caused by a chair catching fire after it was set too close to a wood stove.
Investigators talked with Bruce Fales, 64, in his hospital room.
He told them he was asleep when the fire broke out and he escaped through a bedroom window.
Fales suffered from burns and smoke inhalation and crawled down his driveway where he was found.
Investigators also say the home was not equipped with smoke detectors.